Diff: mbed-os/platform/Callback.h

Revision:

0:8fdf9a60065b

diff -r 000000000000 -r 8fdf9a60065b mbed-os/platform/Callback.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-os/platform/Callback.h	Wed Oct 10 00:33:53 2018 +0000
@@ -0,0 +1,4938 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2015 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef MBED_CALLBACK_H
+#define MBED_CALLBACK_H
+
+#include <string.h>
+#include <stdint.h>
+#include <new>
+#include "platform/mbed_assert.h"
+#include "platform/mbed_toolchain.h"
+
+namespace mbed {
+/** \addtogroup platform */
+/** @{*/
+/**
+ * \defgroup platform_Callback Callback class
+ * @{
+ */
+
+/** Callback class based on template specialization
+ *
+ * @note Synchronization level: Not protected
+ */
+template <typename F>
+class Callback;
+
+// Internal sfinae declarations
+//
+// These are used to eliminate overloads based on type attributes
+// 1. Does a function object have a call operator
+// 2. Does a function object fit in the available storage
+//
+// These eliminations are handled cleanly by the compiler and avoid
+// massive and misleading error messages when confronted with an
+// invalid type (or worse, runtime failures)
+namespace detail {
+struct nil {};
+
+template <bool B, typename R = nil>
+struct enable_if {
+    typedef R type;
+};
+
+template <typename R>
+struct enable_if<false, R> {};
+
+template <typename M, M>
+struct is_type {
+    static const bool value = true;
+};
+}
+
+#define MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, M)                            \
+    typename detail::enable_if<                                             \
+            detail::is_type<M, &F::operator()>::value &&                    \
+            sizeof(F) <= sizeof(uintptr_t)                                  \
+        >::type = detail::nil()
+
+/** Callback class based on template specialization
+ *
+ * @note Synchronization level: Not protected
+ */
+template <typename R>
+class Callback<R()> {
+public:
+    /** Create a Callback with a static function
+     *  @param func     Static function to attach
+     */
+    Callback(R(*func)() = 0)
+    {
+        if (!func) {
+            memset(this, 0, sizeof(Callback));
+        } else {
+            generate(func);
+        }
+    }
+
+    /** Attach a Callback
+     *  @param func     The Callback to attach
+     */
+    Callback(const Callback<R()> &func)
+    {
+        if (func._ops) {
+            func._ops->move(this, &func);
+        }
+        _ops = func._ops;
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(U *obj, R(T::*method)())
+    {
+        generate(method_context<T, R(T::*)()>(obj, method));
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(const U *obj, R(T::*method)() const)
+    {
+        generate(method_context<const T, R(T::*)() const>(obj, method));
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(volatile U *obj, R(T::*method)() volatile)
+    {
+        generate(method_context<volatile T, R(T::*)() volatile>(obj, method));
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(const volatile U *obj, R(T::*method)() const volatile)
+    {
+        generate(method_context<const volatile T, R(T::*)() const volatile>(obj, method));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(T *), U *arg)
+    {
+        generate(function_context<R(*)(T *), T>(func, arg));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(const T *), const U *arg)
+    {
+        generate(function_context<R(*)(const T *), const T>(func, arg));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(volatile T *), volatile U *arg)
+    {
+        generate(function_context<R(*)(volatile T *), volatile T>(func, arg));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(const volatile T *), const volatile U *arg)
+    {
+        generate(function_context<R(*)(const volatile T *), const volatile T>(func, arg));
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)()))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(const F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)() const))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)() volatile))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(const volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)() const volatile))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(U *obj, R(*func)(T *))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(const U *obj, R(*func)(const T *))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(volatile U *obj, R(*func)(volatile T *))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(const volatile U *obj, R(*func)(const volatile T *))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Destroy a callback
+     */
+    ~Callback()
+    {
+        if (_ops) {
+            _ops->dtor(this);
+        }
+    }
+
+    /** Attach a static function
+     *  @param func     Static function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)())
+    {
+        this->~Callback();
+        new (this) Callback(func);
+    }
+
+    /** Attach a Callback
+     *  @param func     The Callback to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const Callback<R()> &func)
+    {
+        this->~Callback();
+        new (this) Callback(func);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(U *obj, R(T::*method)())
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const U *obj, R(T::*method)() const)
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(volatile U *obj, R(T::*method)() volatile)
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const volatile U *obj, R(T::*method)() const volatile)
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(T *), U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(const T *), const U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(volatile T *), volatile U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(const volatile T *), const volatile U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a function object
+     *  @param f     Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)()))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a function object
+     *  @param f     Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)() const))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)() volatile))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)() const volatile))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(U *obj, R(*func)(T *))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(const U *obj, R(*func)(const T *))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(volatile U *obj, R(*func)(volatile T *))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(const volatile U *obj, R(*func)(const volatile T *))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Assign a callback
+     */
+    Callback &operator=(const Callback &that)
+    {
+        if (this != &that) {
+            this->~Callback();
+            new (this) Callback(that);
+        }
+
+        return *this;
+    }
+
+    /** Call the attached function
+     */
+    R call() const
+    {
+        MBED_ASSERT(_ops);
+        return _ops->call(this);
+    }
+
+    /** Call the attached function
+     */
+    R operator()() const
+    {
+        return call();
+    }
+
+    /** Test if function has been attached
+     */
+    operator bool() const
+    {
+        return _ops;
+    }
+
+    /** Test for equality
+     */
+    friend bool operator==(const Callback &l, const Callback &r)
+    {
+        return memcmp(&l, &r, sizeof(Callback)) == 0;
+    }
+
+    /** Test for inequality
+     */
+    friend bool operator!=(const Callback &l, const Callback &r)
+    {
+        return !(l == r);
+    }
+
+    /** Static thunk for passing as C-style function
+     *  @param func Callback to call passed as void pointer
+     *  @return the value as determined by func which is of
+     *      type and determined by the signiture of func
+     */
+    static R thunk(void *func)
+    {
+        return static_cast<Callback *>(func)->call();
+    }
+
+private:
+    // Stored as pointer to function and pointer to optional object
+    // Function pointer is stored as union of possible function types
+    // to guarantee proper size and alignment
+    struct _class;
+    union {
+        void (*_staticfunc)();
+        void (*_boundfunc)(_class *);
+        void (_class::*_methodfunc)();
+    } _func;
+    void *_obj;
+
+    // Dynamically dispatched operations
+    const struct ops {
+        R(*call)(const void *);
+        void (*move)(void *, const void *);
+        void (*dtor)(void *);
+    } *_ops;
+
+    // Generate operations for function object
+    template <typename F>
+    void generate(const F &f)
+    {
+        static const ops ops = {
+            &Callback::function_call<F>,
+            &Callback::function_move<F>,
+            &Callback::function_dtor<F>,
+        };
+
+        MBED_STATIC_ASSERT(sizeof(Callback) - sizeof(_ops) >= sizeof(F),
+                           "Type F must not exceed the size of the Callback class");
+        memset(this, 0, sizeof(Callback));
+        new (this) F(f);
+        _ops = &ops;
+    }
+
+    // Function attributes
+    template <typename F>
+    static R function_call(const void *p)
+    {
+        return (*(F *)p)();
+    }
+
+    template <typename F>
+    static void function_move(void *d, const void *p)
+    {
+        new (d) F(*(F *)p);
+    }
+
+    template <typename F>
+    static void function_dtor(void *p)
+    {
+        ((F *)p)->~F();
+    }
+
+    // Wrappers for functions with context
+    template <typename O, typename M>
+    struct method_context {
+        M method;
+        O *obj;
+
+        method_context(O *obj, M method)
+            : method(method), obj(obj) {}
+
+        R operator()() const
+        {
+            return (obj->*method)();
+        }
+    };
+
+    template <typename F, typename A>
+    struct function_context {
+        F func;
+        A *arg;
+
+        function_context(F func, A *arg)
+            : func(func), arg(arg) {}
+
+        R operator()() const
+        {
+            return func(arg);
+        }
+    };
+};
+
+/** Callback class based on template specialization
+ *
+ * @note Synchronization level: Not protected
+ */
+template <typename R, typename A0>
+class Callback<R(A0)> {
+public:
+    /** Create a Callback with a static function
+     *  @param func     Static function to attach
+     */
+    Callback(R(*func)(A0) = 0)
+    {
+        if (!func) {
+            memset(this, 0, sizeof(Callback));
+        } else {
+            generate(func);
+        }
+    }
+
+    /** Attach a Callback
+     *  @param func     The Callback to attach
+     */
+    Callback(const Callback<R(A0)> &func)
+    {
+        if (func._ops) {
+            func._ops->move(this, &func);
+        }
+        _ops = func._ops;
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(U *obj, R(T::*method)(A0))
+    {
+        generate(method_context<T, R(T::*)(A0)>(obj, method));
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(const U *obj, R(T::*method)(A0) const)
+    {
+        generate(method_context<const T, R(T::*)(A0) const>(obj, method));
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(volatile U *obj, R(T::*method)(A0) volatile)
+    {
+        generate(method_context<volatile T, R(T::*)(A0) volatile>(obj, method));
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(const volatile U *obj, R(T::*method)(A0) const volatile)
+    {
+        generate(method_context<const volatile T, R(T::*)(A0) const volatile>(obj, method));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(T *, A0), U *arg)
+    {
+        generate(function_context<R(*)(T *, A0), T>(func, arg));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(const T *, A0), const U *arg)
+    {
+        generate(function_context<R(*)(const T *, A0), const T>(func, arg));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(volatile T *, A0), volatile U *arg)
+    {
+        generate(function_context<R(*)(volatile T *, A0), volatile T>(func, arg));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(const volatile T *, A0), const volatile U *arg)
+    {
+        generate(function_context<R(*)(const volatile T *, A0), const volatile T>(func, arg));
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0)))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(const F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0) const))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0) volatile))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(const volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0) const volatile))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(U *obj, R(*func)(T *, A0))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(const U *obj, R(*func)(const T *, A0))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(volatile U *obj, R(*func)(volatile T *, A0))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(const volatile U *obj, R(*func)(const volatile T *, A0))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Destroy a callback
+     */
+    ~Callback()
+    {
+        if (_ops) {
+            _ops->dtor(this);
+        }
+    }
+
+    /** Attach a static function
+     *  @param func     Static function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(A0))
+    {
+        this->~Callback();
+        new (this) Callback(func);
+    }
+
+    /** Attach a Callback
+     *  @param func     The Callback to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const Callback<R(A0)> &func)
+    {
+        this->~Callback();
+        new (this) Callback(func);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(U *obj, R(T::*method)(A0))
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const U *obj, R(T::*method)(A0) const)
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(volatile U *obj, R(T::*method)(A0) volatile)
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const volatile U *obj, R(T::*method)(A0) const volatile)
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(T *, A0), U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(const T *, A0), const U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(volatile T *, A0), volatile U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(const volatile T *, A0), const volatile U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0)))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0) const))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0) volatile))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0) const volatile))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(U *obj, R(*func)(T *, A0))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(const U *obj, R(*func)(const T *, A0))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(volatile U *obj, R(*func)(volatile T *, A0))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(const volatile U *obj, R(*func)(const volatile T *, A0))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Assign a callback
+     */
+    Callback &operator=(const Callback &that)
+    {
+        if (this != &that) {
+            this->~Callback();
+            new (this) Callback(that);
+        }
+
+        return *this;
+    }
+
+    /** Call the attached function
+     */
+    R call(A0 a0) const
+    {
+        MBED_ASSERT(_ops);
+        return _ops->call(this, a0);
+    }
+
+    /** Call the attached function
+     */
+    R operator()(A0 a0) const
+    {
+        return call(a0);
+    }
+
+    /** Test if function has been attached
+     */
+    operator bool() const
+    {
+        return _ops;
+    }
+
+    /** Test for equality
+     */
+    friend bool operator==(const Callback &l, const Callback &r)
+    {
+        return memcmp(&l, &r, sizeof(Callback)) == 0;
+    }
+
+    /** Test for inequality
+     */
+    friend bool operator!=(const Callback &l, const Callback &r)
+    {
+        return !(l == r);
+    }
+
+    /** Static thunk for passing as C-style function
+     *  @param func Callback to call passed as void pointer
+     *  @param a0 An argument to be called with function func
+     *  @return the value as determined by func which is of
+     *      type and determined by the signiture of func
+     */
+    static R thunk(void *func, A0 a0)
+    {
+        return static_cast<Callback *>(func)->call(a0);
+    }
+
+private:
+    // Stored as pointer to function and pointer to optional object
+    // Function pointer is stored as union of possible function types
+    // to guarantee proper size and alignment
+    struct _class;
+    union {
+        void (*_staticfunc)(A0);
+        void (*_boundfunc)(_class *, A0);
+        void (_class::*_methodfunc)(A0);
+    } _func;
+    void *_obj;
+
+    // Dynamically dispatched operations
+    const struct ops {
+        R(*call)(const void *, A0);
+        void (*move)(void *, const void *);
+        void (*dtor)(void *);
+    } *_ops;
+
+    // Generate operations for function object
+    template <typename F>
+    void generate(const F &f)
+    {
+        static const ops ops = {
+            &Callback::function_call<F>,
+            &Callback::function_move<F>,
+            &Callback::function_dtor<F>,
+        };
+
+        MBED_STATIC_ASSERT(sizeof(Callback) - sizeof(_ops) >= sizeof(F),
+                           "Type F must not exceed the size of the Callback class");
+        memset(this, 0, sizeof(Callback));
+        new (this) F(f);
+        _ops = &ops;
+    }
+
+    // Function attributes
+    template <typename F>
+    static R function_call(const void *p, A0 a0)
+    {
+        return (*(F *)p)(a0);
+    }
+
+    template <typename F>
+    static void function_move(void *d, const void *p)
+    {
+        new (d) F(*(F *)p);
+    }
+
+    template <typename F>
+    static void function_dtor(void *p)
+    {
+        ((F *)p)->~F();
+    }
+
+    // Wrappers for functions with context
+    template <typename O, typename M>
+    struct method_context {
+        M method;
+        O *obj;
+
+        method_context(O *obj, M method)
+            : method(method), obj(obj) {}
+
+        R operator()(A0 a0) const
+        {
+            return (obj->*method)(a0);
+        }
+    };
+
+    template <typename F, typename A>
+    struct function_context {
+        F func;
+        A *arg;
+
+        function_context(F func, A *arg)
+            : func(func), arg(arg) {}
+
+        R operator()(A0 a0) const
+        {
+            return func(arg, a0);
+        }
+    };
+};
+
+/** Callback class based on template specialization
+ *
+ * @note Synchronization level: Not protected
+ */
+template <typename R, typename A0, typename A1>
+class Callback<R(A0, A1)> {
+public:
+    /** Create a Callback with a static function
+     *  @param func     Static function to attach
+     */
+    Callback(R(*func)(A0, A1) = 0)
+    {
+        if (!func) {
+            memset(this, 0, sizeof(Callback));
+        } else {
+            generate(func);
+        }
+    }
+
+    /** Attach a Callback
+     *  @param func     The Callback to attach
+     */
+    Callback(const Callback<R(A0, A1)> &func)
+    {
+        if (func._ops) {
+            func._ops->move(this, &func);
+        }
+        _ops = func._ops;
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(U *obj, R(T::*method)(A0, A1))
+    {
+        generate(method_context<T, R(T::*)(A0, A1)>(obj, method));
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(const U *obj, R(T::*method)(A0, A1) const)
+    {
+        generate(method_context<const T, R(T::*)(A0, A1) const>(obj, method));
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(volatile U *obj, R(T::*method)(A0, A1) volatile)
+    {
+        generate(method_context<volatile T, R(T::*)(A0, A1) volatile>(obj, method));
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(const volatile U *obj, R(T::*method)(A0, A1) const volatile)
+    {
+        generate(method_context<const volatile T, R(T::*)(A0, A1) const volatile>(obj, method));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(T *, A0, A1), U *arg)
+    {
+        generate(function_context<R(*)(T *, A0, A1), T>(func, arg));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(const T *, A0, A1), const U *arg)
+    {
+        generate(function_context<R(*)(const T *, A0, A1), const T>(func, arg));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(volatile T *, A0, A1), volatile U *arg)
+    {
+        generate(function_context<R(*)(volatile T *, A0, A1), volatile T>(func, arg));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(const volatile T *, A0, A1), const volatile U *arg)
+    {
+        generate(function_context<R(*)(const volatile T *, A0, A1), const volatile T>(func, arg));
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1)))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(const F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1) const))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1) volatile))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(const volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1) const volatile))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(U *obj, R(*func)(T *, A0, A1))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(const U *obj, R(*func)(const T *, A0, A1))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(volatile U *obj, R(*func)(volatile T *, A0, A1))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(const volatile U *obj, R(*func)(const volatile T *, A0, A1))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Destroy a callback
+     */
+    ~Callback()
+    {
+        if (_ops) {
+            _ops->dtor(this);
+        }
+    }
+
+    /** Attach a static function
+     *  @param func     Static function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(A0, A1))
+    {
+        this->~Callback();
+        new (this) Callback(func);
+    }
+
+    /** Attach a Callback
+     *  @param func     The Callback to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const Callback<R(A0, A1)> &func)
+    {
+        this->~Callback();
+        new (this) Callback(func);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(U *obj, R(T::*method)(A0, A1))
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const U *obj, R(T::*method)(A0, A1) const)
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(volatile U *obj, R(T::*method)(A0, A1) volatile)
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const volatile U *obj, R(T::*method)(A0, A1) const volatile)
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(T *, A0, A1), U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(const T *, A0, A1), const U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(volatile T *, A0, A1), volatile U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(const volatile T *, A0, A1), const volatile U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1)))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1) const))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1) volatile))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1) const volatile))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(U *obj, R(*func)(T *, A0, A1))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(const U *obj, R(*func)(const T *, A0, A1))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(volatile U *obj, R(*func)(volatile T *, A0, A1))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(const volatile U *obj, R(*func)(const volatile T *, A0, A1))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Assign a callback
+     */
+    Callback &operator=(const Callback &that)
+    {
+        if (this != &that) {
+            this->~Callback();
+            new (this) Callback(that);
+        }
+
+        return *this;
+    }
+
+    /** Call the attached function
+     */
+    R call(A0 a0, A1 a1) const
+    {
+        MBED_ASSERT(_ops);
+        return _ops->call(this, a0, a1);
+    }
+
+    /** Call the attached function
+     */
+    R operator()(A0 a0, A1 a1) const
+    {
+        return call(a0, a1);
+    }
+
+    /** Test if function has been attached
+     */
+    operator bool() const
+    {
+        return _ops;
+    }
+
+    /** Test for equality
+     */
+    friend bool operator==(const Callback &l, const Callback &r)
+    {
+        return memcmp(&l, &r, sizeof(Callback)) == 0;
+    }
+
+    /** Test for inequality
+     */
+    friend bool operator!=(const Callback &l, const Callback &r)
+    {
+        return !(l == r);
+    }
+
+    /** Static thunk for passing as C-style function
+     *  @param func Callback to call passed as void pointer
+     *  @param a0 An argument to be called with function func
+     *  @param a1 An argument to be called with function func
+     *  @return the value as determined by func which is of
+     *      type and determined by the signiture of func
+     */
+    static R thunk(void *func, A0 a0, A1 a1)
+    {
+        return static_cast<Callback *>(func)->call(a0, a1);
+    }
+
+private:
+    // Stored as pointer to function and pointer to optional object
+    // Function pointer is stored as union of possible function types
+    // to guarantee proper size and alignment
+    struct _class;
+    union {
+        void (*_staticfunc)(A0, A1);
+        void (*_boundfunc)(_class *, A0, A1);
+        void (_class::*_methodfunc)(A0, A1);
+    } _func;
+    void *_obj;
+
+    // Dynamically dispatched operations
+    const struct ops {
+        R(*call)(const void *, A0, A1);
+        void (*move)(void *, const void *);
+        void (*dtor)(void *);
+    } *_ops;
+
+    // Generate operations for function object
+    template <typename F>
+    void generate(const F &f)
+    {
+        static const ops ops = {
+            &Callback::function_call<F>,
+            &Callback::function_move<F>,
+            &Callback::function_dtor<F>,
+        };
+
+        MBED_STATIC_ASSERT(sizeof(Callback) - sizeof(_ops) >= sizeof(F),
+                           "Type F must not exceed the size of the Callback class");
+        memset(this, 0, sizeof(Callback));
+        new (this) F(f);
+        _ops = &ops;
+    }
+
+    // Function attributes
+    template <typename F>
+    static R function_call(const void *p, A0 a0, A1 a1)
+    {
+        return (*(F *)p)(a0, a1);
+    }
+
+    template <typename F>
+    static void function_move(void *d, const void *p)
+    {
+        new (d) F(*(F *)p);
+    }
+
+    template <typename F>
+    static void function_dtor(void *p)
+    {
+        ((F *)p)->~F();
+    }
+
+    // Wrappers for functions with context
+    template <typename O, typename M>
+    struct method_context {
+        M method;
+        O *obj;
+
+        method_context(O *obj, M method)
+            : method(method), obj(obj) {}
+
+        R operator()(A0 a0, A1 a1) const
+        {
+            return (obj->*method)(a0, a1);
+        }
+    };
+
+    template <typename F, typename A>
+    struct function_context {
+        F func;
+        A *arg;
+
+        function_context(F func, A *arg)
+            : func(func), arg(arg) {}
+
+        R operator()(A0 a0, A1 a1) const
+        {
+            return func(arg, a0, a1);
+        }
+    };
+};
+
+/** Callback class based on template specialization
+ *
+ * @note Synchronization level: Not protected
+ */
+template <typename R, typename A0, typename A1, typename A2>
+class Callback<R(A0, A1, A2)> {
+public:
+    /** Create a Callback with a static function
+     *  @param func     Static function to attach
+     */
+    Callback(R(*func)(A0, A1, A2) = 0)
+    {
+        if (!func) {
+            memset(this, 0, sizeof(Callback));
+        } else {
+            generate(func);
+        }
+    }
+
+    /** Attach a Callback
+     *  @param func     The Callback to attach
+     */
+    Callback(const Callback<R(A0, A1, A2)> &func)
+    {
+        if (func._ops) {
+            func._ops->move(this, &func);
+        }
+        _ops = func._ops;
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(U *obj, R(T::*method)(A0, A1, A2))
+    {
+        generate(method_context<T, R(T::*)(A0, A1, A2)>(obj, method));
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(const U *obj, R(T::*method)(A0, A1, A2) const)
+    {
+        generate(method_context<const T, R(T::*)(A0, A1, A2) const>(obj, method));
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(volatile U *obj, R(T::*method)(A0, A1, A2) volatile)
+    {
+        generate(method_context<volatile T, R(T::*)(A0, A1, A2) volatile>(obj, method));
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(const volatile U *obj, R(T::*method)(A0, A1, A2) const volatile)
+    {
+        generate(method_context<const volatile T, R(T::*)(A0, A1, A2) const volatile>(obj, method));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(T *, A0, A1, A2), U *arg)
+    {
+        generate(function_context<R(*)(T *, A0, A1, A2), T>(func, arg));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(const T *, A0, A1, A2), const U *arg)
+    {
+        generate(function_context<R(*)(const T *, A0, A1, A2), const T>(func, arg));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(volatile T *, A0, A1, A2), volatile U *arg)
+    {
+        generate(function_context<R(*)(volatile T *, A0, A1, A2), volatile T>(func, arg));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(const volatile T *, A0, A1, A2), const volatile U *arg)
+    {
+        generate(function_context<R(*)(const volatile T *, A0, A1, A2), const volatile T>(func, arg));
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2)))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(const F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2) const))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2) volatile))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(const volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2) const volatile))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(U *obj, R(*func)(T *, A0, A1, A2))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(const U *obj, R(*func)(const T *, A0, A1, A2))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(volatile U *obj, R(*func)(volatile T *, A0, A1, A2))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(const volatile U *obj, R(*func)(const volatile T *, A0, A1, A2))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Destroy a callback
+     */
+    ~Callback()
+    {
+        if (_ops) {
+            _ops->dtor(this);
+        }
+    }
+
+    /** Attach a static function
+     *  @param func     Static function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(A0, A1, A2))
+    {
+        this->~Callback();
+        new (this) Callback(func);
+    }
+
+    /** Attach a Callback
+     *  @param func     The Callback to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const Callback<R(A0, A1, A2)> &func)
+    {
+        this->~Callback();
+        new (this) Callback(func);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(U *obj, R(T::*method)(A0, A1, A2))
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const U *obj, R(T::*method)(A0, A1, A2) const)
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(volatile U *obj, R(T::*method)(A0, A1, A2) volatile)
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const volatile U *obj, R(T::*method)(A0, A1, A2) const volatile)
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(T *, A0, A1, A2), U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(const T *, A0, A1, A2), const U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(volatile T *, A0, A1, A2), volatile U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(const volatile T *, A0, A1, A2), const volatile U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2)))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2) const))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2) volatile))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2) const volatile))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(U *obj, R(*func)(T *, A0, A1, A2))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(const U *obj, R(*func)(const T *, A0, A1, A2))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(volatile U *obj, R(*func)(volatile T *, A0, A1, A2))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(const volatile U *obj, R(*func)(const volatile T *, A0, A1, A2))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Assign a callback
+     */
+    Callback &operator=(const Callback &that)
+    {
+        if (this != &that) {
+            this->~Callback();
+            new (this) Callback(that);
+        }
+
+        return *this;
+    }
+
+    /** Call the attached function
+     */
+    R call(A0 a0, A1 a1, A2 a2) const
+    {
+        MBED_ASSERT(_ops);
+        return _ops->call(this, a0, a1, a2);
+    }
+
+    /** Call the attached function
+     */
+    R operator()(A0 a0, A1 a1, A2 a2) const
+    {
+        return call(a0, a1, a2);
+    }
+
+    /** Test if function has been attached
+     */
+    operator bool() const
+    {
+        return _ops;
+    }
+
+    /** Test for equality
+     */
+    friend bool operator==(const Callback &l, const Callback &r)
+    {
+        return memcmp(&l, &r, sizeof(Callback)) == 0;
+    }
+
+    /** Test for inequality
+     */
+    friend bool operator!=(const Callback &l, const Callback &r)
+    {
+        return !(l == r);
+    }
+
+    /** Static thunk for passing as C-style function
+     *  @param func Callback to call passed as void pointer
+     *  @param a0 An argument to be called with function func
+     *  @param a1 An argument to be called with function func
+     *  @param a2 An argument to be called with function func
+     *  @return the value as determined by func which is of
+     *      type and determined by the signiture of func
+     */
+    static R thunk(void *func, A0 a0, A1 a1, A2 a2)
+    {
+        return static_cast<Callback *>(func)->call(a0, a1, a2);
+    }
+
+private:
+    // Stored as pointer to function and pointer to optional object
+    // Function pointer is stored as union of possible function types
+    // to guarantee proper size and alignment
+    struct _class;
+    union {
+        void (*_staticfunc)(A0, A1, A2);
+        void (*_boundfunc)(_class *, A0, A1, A2);
+        void (_class::*_methodfunc)(A0, A1, A2);
+    } _func;
+    void *_obj;
+
+    // Dynamically dispatched operations
+    const struct ops {
+        R(*call)(const void *, A0, A1, A2);
+        void (*move)(void *, const void *);
+        void (*dtor)(void *);
+    } *_ops;
+
+    // Generate operations for function object
+    template <typename F>
+    void generate(const F &f)
+    {
+        static const ops ops = {
+            &Callback::function_call<F>,
+            &Callback::function_move<F>,
+            &Callback::function_dtor<F>,
+        };
+
+        MBED_STATIC_ASSERT(sizeof(Callback) - sizeof(_ops) >= sizeof(F),
+                           "Type F must not exceed the size of the Callback class");
+        memset(this, 0, sizeof(Callback));
+        new (this) F(f);
+        _ops = &ops;
+    }
+
+    // Function attributes
+    template <typename F>
+    static R function_call(const void *p, A0 a0, A1 a1, A2 a2)
+    {
+        return (*(F *)p)(a0, a1, a2);
+    }
+
+    template <typename F>
+    static void function_move(void *d, const void *p)
+    {
+        new (d) F(*(F *)p);
+    }
+
+    template <typename F>
+    static void function_dtor(void *p)
+    {
+        ((F *)p)->~F();
+    }
+
+    // Wrappers for functions with context
+    template <typename O, typename M>
+    struct method_context {
+        M method;
+        O *obj;
+
+        method_context(O *obj, M method)
+            : method(method), obj(obj) {}
+
+        R operator()(A0 a0, A1 a1, A2 a2) const
+        {
+            return (obj->*method)(a0, a1, a2);
+        }
+    };
+
+    template <typename F, typename A>
+    struct function_context {
+        F func;
+        A *arg;
+
+        function_context(F func, A *arg)
+            : func(func), arg(arg) {}
+
+        R operator()(A0 a0, A1 a1, A2 a2) const
+        {
+            return func(arg, a0, a1, a2);
+        }
+    };
+};
+
+/** Callback class based on template specialization
+ *
+ * @note Synchronization level: Not protected
+ */
+template <typename R, typename A0, typename A1, typename A2, typename A3>
+class Callback<R(A0, A1, A2, A3)> {
+public:
+    /** Create a Callback with a static function
+     *  @param func     Static function to attach
+     */
+    Callback(R(*func)(A0, A1, A2, A3) = 0)
+    {
+        if (!func) {
+            memset(this, 0, sizeof(Callback));
+        } else {
+            generate(func);
+        }
+    }
+
+    /** Attach a Callback
+     *  @param func     The Callback to attach
+     */
+    Callback(const Callback<R(A0, A1, A2, A3)> &func)
+    {
+        if (func._ops) {
+            func._ops->move(this, &func);
+        }
+        _ops = func._ops;
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(U *obj, R(T::*method)(A0, A1, A2, A3))
+    {
+        generate(method_context<T, R(T::*)(A0, A1, A2, A3)>(obj, method));
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(const U *obj, R(T::*method)(A0, A1, A2, A3) const)
+    {
+        generate(method_context<const T, R(T::*)(A0, A1, A2, A3) const>(obj, method));
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(volatile U *obj, R(T::*method)(A0, A1, A2, A3) volatile)
+    {
+        generate(method_context<volatile T, R(T::*)(A0, A1, A2, A3) volatile>(obj, method));
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(const volatile U *obj, R(T::*method)(A0, A1, A2, A3) const volatile)
+    {
+        generate(method_context<const volatile T, R(T::*)(A0, A1, A2, A3) const volatile>(obj, method));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(T *, A0, A1, A2, A3), U *arg)
+    {
+        generate(function_context<R(*)(T *, A0, A1, A2, A3), T>(func, arg));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(const T *, A0, A1, A2, A3), const U *arg)
+    {
+        generate(function_context<R(*)(const T *, A0, A1, A2, A3), const T>(func, arg));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(volatile T *, A0, A1, A2, A3), volatile U *arg)
+    {
+        generate(function_context<R(*)(volatile T *, A0, A1, A2, A3), volatile T>(func, arg));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(const volatile T *, A0, A1, A2, A3), const volatile U *arg)
+    {
+        generate(function_context<R(*)(const volatile T *, A0, A1, A2, A3), const volatile T>(func, arg));
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2, A3)))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(const F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2, A3) const))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2, A3) volatile))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(const volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2, A3) const volatile))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(U *obj, R(*func)(T *, A0, A1, A2, A3))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(const U *obj, R(*func)(const T *, A0, A1, A2, A3))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(volatile U *obj, R(*func)(volatile T *, A0, A1, A2, A3))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(const volatile U *obj, R(*func)(const volatile T *, A0, A1, A2, A3))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Destroy a callback
+     */
+    ~Callback()
+    {
+        if (_ops) {
+            _ops->dtor(this);
+        }
+    }
+
+    /** Attach a static function
+     *  @param func     Static function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(A0, A1, A2, A3))
+    {
+        this->~Callback();
+        new (this) Callback(func);
+    }
+
+    /** Attach a Callback
+     *  @param func     The Callback to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const Callback<R(A0, A1, A2, A3)> &func)
+    {
+        this->~Callback();
+        new (this) Callback(func);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(U *obj, R(T::*method)(A0, A1, A2, A3))
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const U *obj, R(T::*method)(A0, A1, A2, A3) const)
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(volatile U *obj, R(T::*method)(A0, A1, A2, A3) volatile)
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const volatile U *obj, R(T::*method)(A0, A1, A2, A3) const volatile)
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(T *, A0, A1, A2, A3), U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(const T *, A0, A1, A2, A3), const U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(volatile T *, A0, A1, A2, A3), volatile U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(const volatile T *, A0, A1, A2, A3), const volatile U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2, A3)))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2, A3) const))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2, A3) volatile))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2, A3) const volatile))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(U *obj, R(*func)(T *, A0, A1, A2, A3))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(const U *obj, R(*func)(const T *, A0, A1, A2, A3))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(volatile U *obj, R(*func)(volatile T *, A0, A1, A2, A3))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(const volatile U *obj, R(*func)(const volatile T *, A0, A1, A2, A3))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Assign a callback
+     */
+    Callback &operator=(const Callback &that)
+    {
+        if (this != &that) {
+            this->~Callback();
+            new (this) Callback(that);
+        }
+
+        return *this;
+    }
+
+    /** Call the attached function
+     */
+    R call(A0 a0, A1 a1, A2 a2, A3 a3) const
+    {
+        MBED_ASSERT(_ops);
+        return _ops->call(this, a0, a1, a2, a3);
+    }
+
+    /** Call the attached function
+     */
+    R operator()(A0 a0, A1 a1, A2 a2, A3 a3) const
+    {
+        return call(a0, a1, a2, a3);
+    }
+
+    /** Test if function has been attached
+     */
+    operator bool() const
+    {
+        return _ops;
+    }
+
+    /** Test for equality
+     */
+    friend bool operator==(const Callback &l, const Callback &r)
+    {
+        return memcmp(&l, &r, sizeof(Callback)) == 0;
+    }
+
+    /** Test for inequality
+     */
+    friend bool operator!=(const Callback &l, const Callback &r)
+    {
+        return !(l == r);
+    }
+
+    /** Static thunk for passing as C-style function
+     *  @param func Callback to call passed as void pointer
+     *  @param a0 An argument to be called with function func
+     *  @param a1 An argument to be called with function func
+     *  @param a2 An argument to be called with function func
+     *  @param a3 An argument to be called with function func
+     *  @return the value as determined by func which is of
+     *      type and determined by the signiture of func
+     */
+    static R thunk(void *func, A0 a0, A1 a1, A2 a2, A3 a3)
+    {
+        return static_cast<Callback *>(func)->call(a0, a1, a2, a3);
+    }
+
+private:
+    // Stored as pointer to function and pointer to optional object
+    // Function pointer is stored as union of possible function types
+    // to guarantee proper size and alignment
+    struct _class;
+    union {
+        void (*_staticfunc)(A0, A1, A2, A3);
+        void (*_boundfunc)(_class *, A0, A1, A2, A3);
+        void (_class::*_methodfunc)(A0, A1, A2, A3);
+    } _func;
+    void *_obj;
+
+    // Dynamically dispatched operations
+    const struct ops {
+        R(*call)(const void *, A0, A1, A2, A3);
+        void (*move)(void *, const void *);
+        void (*dtor)(void *);
+    } *_ops;
+
+    // Generate operations for function object
+    template <typename F>
+    void generate(const F &f)
+    {
+        static const ops ops = {
+            &Callback::function_call<F>,
+            &Callback::function_move<F>,
+            &Callback::function_dtor<F>,
+        };
+
+        MBED_STATIC_ASSERT(sizeof(Callback) - sizeof(_ops) >= sizeof(F),
+                           "Type F must not exceed the size of the Callback class");
+        memset(this, 0, sizeof(Callback));
+        new (this) F(f);
+        _ops = &ops;
+    }
+
+    // Function attributes
+    template <typename F>
+    static R function_call(const void *p, A0 a0, A1 a1, A2 a2, A3 a3)
+    {
+        return (*(F *)p)(a0, a1, a2, a3);
+    }
+
+    template <typename F>
+    static void function_move(void *d, const void *p)
+    {
+        new (d) F(*(F *)p);
+    }
+
+    template <typename F>
+    static void function_dtor(void *p)
+    {
+        ((F *)p)->~F();
+    }
+
+    // Wrappers for functions with context
+    template <typename O, typename M>
+    struct method_context {
+        M method;
+        O *obj;
+
+        method_context(O *obj, M method)
+            : method(method), obj(obj) {}
+
+        R operator()(A0 a0, A1 a1, A2 a2, A3 a3) const
+        {
+            return (obj->*method)(a0, a1, a2, a3);
+        }
+    };
+
+    template <typename F, typename A>
+    struct function_context {
+        F func;
+        A *arg;
+
+        function_context(F func, A *arg)
+            : func(func), arg(arg) {}
+
+        R operator()(A0 a0, A1 a1, A2 a2, A3 a3) const
+        {
+            return func(arg, a0, a1, a2, a3);
+        }
+    };
+};
+
+/** Callback class based on template specialization
+ *
+ * @note Synchronization level: Not protected
+ */
+template <typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+class Callback<R(A0, A1, A2, A3, A4)> {
+public:
+    /** Create a Callback with a static function
+     *  @param func     Static function to attach
+     */
+    Callback(R(*func)(A0, A1, A2, A3, A4) = 0)
+    {
+        if (!func) {
+            memset(this, 0, sizeof(Callback));
+        } else {
+            generate(func);
+        }
+    }
+
+    /** Attach a Callback
+     *  @param func     The Callback to attach
+     */
+    Callback(const Callback<R(A0, A1, A2, A3, A4)> &func)
+    {
+        if (func._ops) {
+            func._ops->move(this, &func);
+        }
+        _ops = func._ops;
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(U *obj, R(T::*method)(A0, A1, A2, A3, A4))
+    {
+        generate(method_context<T, R(T::*)(A0, A1, A2, A3, A4)>(obj, method));
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(const U *obj, R(T::*method)(A0, A1, A2, A3, A4) const)
+    {
+        generate(method_context<const T, R(T::*)(A0, A1, A2, A3, A4) const>(obj, method));
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(volatile U *obj, R(T::*method)(A0, A1, A2, A3, A4) volatile)
+    {
+        generate(method_context<volatile T, R(T::*)(A0, A1, A2, A3, A4) volatile>(obj, method));
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     */
+    template<typename T, typename U>
+    Callback(const volatile U *obj, R(T::*method)(A0, A1, A2, A3, A4) const volatile)
+    {
+        generate(method_context<const volatile T, R(T::*)(A0, A1, A2, A3, A4) const volatile>(obj, method));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(T *, A0, A1, A2, A3, A4), U *arg)
+    {
+        generate(function_context<R(*)(T *, A0, A1, A2, A3, A4), T>(func, arg));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(const T *, A0, A1, A2, A3, A4), const U *arg)
+    {
+        generate(function_context<R(*)(const T *, A0, A1, A2, A3, A4), const T>(func, arg));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(volatile T *, A0, A1, A2, A3, A4), volatile U *arg)
+    {
+        generate(function_context<R(*)(volatile T *, A0, A1, A2, A3, A4), volatile T>(func, arg));
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     */
+    template<typename T, typename U>
+    Callback(R(*func)(const volatile T *, A0, A1, A2, A3, A4), const volatile U *arg)
+    {
+        generate(function_context<R(*)(const volatile T *, A0, A1, A2, A3, A4), const volatile T>(func, arg));
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2, A3, A4)))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(const F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2, A3, A4) const))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2, A3, A4) volatile))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     */
+    template <typename F>
+    Callback(const volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2, A3, A4) const volatile))
+    {
+        generate(f);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(U *obj, R(*func)(T *, A0, A1, A2, A3, A4))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(const U *obj, R(*func)(const T *, A0, A1, A2, A3, A4))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(volatile U *obj, R(*func)(volatile T *, A0, A1, A2, A3, A4))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to Callback(func, arg)
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to Callback(func, arg)")
+    Callback(const volatile U *obj, R(*func)(const volatile T *, A0, A1, A2, A3, A4))
+    {
+        new (this) Callback(func, obj);
+    }
+
+    /** Destroy a callback
+     */
+    ~Callback()
+    {
+        if (_ops) {
+            _ops->dtor(this);
+        }
+    }
+
+    /** Attach a static function
+     *  @param func     Static function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(A0, A1, A2, A3, A4))
+    {
+        this->~Callback();
+        new (this) Callback(func);
+    }
+
+    /** Attach a Callback
+     *  @param func     The Callback to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const Callback<R(A0, A1, A2, A3, A4)> &func)
+    {
+        this->~Callback();
+        new (this) Callback(func);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(U *obj, R(T::*method)(A0, A1, A2, A3, A4))
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const U *obj, R(T::*method)(A0, A1, A2, A3, A4) const)
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(volatile U *obj, R(T::*method)(A0, A1, A2, A3, A4) volatile)
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a member function
+     *  @param obj      Pointer to object to invoke member function on
+     *  @param method   Member function to attach
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template<typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const volatile U *obj, R(T::*method)(A0, A1, A2, A3, A4) const volatile)
+    {
+        this->~Callback();
+        new (this) Callback(obj, method);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(T *, A0, A1, A2, A3, A4), U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(const T *, A0, A1, A2, A3, A4), const U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(volatile T *, A0, A1, A2, A3, A4), volatile U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param func     Static function to attach
+     *  @param arg      Pointer argument to function
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(R(*func)(const volatile T *, A0, A1, A2, A3, A4), const volatile U *arg)
+    {
+        this->~Callback();
+        new (this) Callback(func, arg);
+    }
+
+    /** Attach a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2, A3, A4)))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2, A3, A4) const))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2, A3, A4) volatile))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a function object
+     *  @param f Function object to attach
+     *  @note The function object is limited to a single word of storage
+     *  @deprecated
+     *      Replaced by simple assignment 'Callback cb = func'
+     */
+    template <typename F>
+    MBED_DEPRECATED_SINCE("mbed-os-5.4",
+                          "Replaced by simple assignment 'Callback cb = func")
+    void attach(const volatile F f, MBED_ENABLE_IF_CALLBACK_COMPATIBLE(F, R(F::*)(A0, A1, A2, A3, A4) const volatile))
+    {
+        this->~Callback();
+        new (this) Callback(f);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(U *obj, R(*func)(T *, A0, A1, A2, A3, A4))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(const U *obj, R(*func)(const T *, A0, A1, A2, A3, A4))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(volatile U *obj, R(*func)(volatile T *, A0, A1, A2, A3, A4))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     *  @deprecated
+     *      Arguments to callback have been reordered to attach(func, arg)
+     */
+    template <typename T, typename U>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                          "Arguments to callback have been reordered to attach(func, arg)")
+    void attach(const volatile U *obj, R(*func)(const volatile T *, A0, A1, A2, A3, A4))
+    {
+        this->~Callback();
+        new (this) Callback(func, obj);
+    }
+
+    /** Assign a callback
+     */
+    Callback &operator=(const Callback &that)
+    {
+        if (this != &that) {
+            this->~Callback();
+            new (this) Callback(that);
+        }
+
+        return *this;
+    }
+
+    /** Call the attached function
+     */
+    R call(A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) const
+    {
+        MBED_ASSERT(_ops);
+        return _ops->call(this, a0, a1, a2, a3, a4);
+    }
+
+    /** Call the attached function
+     */
+    R operator()(A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) const
+    {
+        return call(a0, a1, a2, a3, a4);
+    }
+
+    /** Test if function has been attached
+     */
+    operator bool() const
+    {
+        return _ops;
+    }
+
+    /** Test for equality
+     */
+    friend bool operator==(const Callback &l, const Callback &r)
+    {
+        return memcmp(&l, &r, sizeof(Callback)) == 0;
+    }
+
+    /** Test for inequality
+     */
+    friend bool operator!=(const Callback &l, const Callback &r)
+    {
+        return !(l == r);
+    }
+
+    /** Static thunk for passing as C-style function
+     *  @param func Callback to call passed as void pointer
+     *  @param a0 An argument to be called with function func
+     *  @param a1 An argument to be called with function func
+     *  @param a2 An argument to be called with function func
+     *  @param a3 An argument to be called with function func
+     *  @param a4 An argument to be called with function func
+     *  @return the value as determined by func which is of
+     *      type and determined by the signiture of func
+     */
+    static R thunk(void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4)
+    {
+        return static_cast<Callback *>(func)->call(a0, a1, a2, a3, a4);
+    }
+
+private:
+    // Stored as pointer to function and pointer to optional object
+    // Function pointer is stored as union of possible function types
+    // to guarantee proper size and alignment
+    struct _class;
+    union {
+        void (*_staticfunc)(A0, A1, A2, A3, A4);
+        void (*_boundfunc)(_class *, A0, A1, A2, A3, A4);
+        void (_class::*_methodfunc)(A0, A1, A2, A3, A4);
+    } _func;
+    void *_obj;
+
+    // Dynamically dispatched operations
+    const struct ops {
+        R(*call)(const void *, A0, A1, A2, A3, A4);
+        void (*move)(void *, const void *);
+        void (*dtor)(void *);
+    } *_ops;
+
+    // Generate operations for function object
+    template <typename F>
+    void generate(const F &f)
+    {
+        static const ops ops = {
+            &Callback::function_call<F>,
+            &Callback::function_move<F>,
+            &Callback::function_dtor<F>,
+        };
+
+        MBED_STATIC_ASSERT(sizeof(Callback) - sizeof(_ops) >= sizeof(F),
+                           "Type F must not exceed the size of the Callback class");
+        memset(this, 0, sizeof(Callback));
+        new (this) F(f);
+        _ops = &ops;
+    }
+
+    // Function attributes
+    template <typename F>
+    static R function_call(const void *p, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4)
+    {
+        return (*(F *)p)(a0, a1, a2, a3, a4);
+    }
+
+    template <typename F>
+    static void function_move(void *d, const void *p)
+    {
+        new (d) F(*(F *)p);
+    }
+
+    template <typename F>
+    static void function_dtor(void *p)
+    {
+        ((F *)p)->~F();
+    }
+
+    // Wrappers for functions with context
+    template <typename O, typename M>
+    struct method_context {
+        M method;
+        O *obj;
+
+        method_context(O *obj, M method)
+            : method(method), obj(obj) {}
+
+        R operator()(A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) const
+        {
+            return (obj->*method)(a0, a1, a2, a3, a4);
+        }
+    };
+
+    template <typename F, typename A>
+    struct function_context {
+        F func;
+        A *arg;
+
+        function_context(F func, A *arg)
+            : func(func), arg(arg) {}
+
+        R operator()(A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) const
+        {
+            return func(arg, a0, a1, a2, a3, a4);
+        }
+    };
+};
+
+// Internally used event type
+typedef Callback<void(int)> event_callback_t;
+
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @return         Callback with infered type
+ */
+template <typename R>
+Callback<R()> callback(R(*func)() = 0)
+{
+    return Callback<R()>(func);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @return         Callback with infered type
+ */
+template <typename R>
+Callback<R()> callback(const Callback<R()> &func)
+{
+    return Callback<R()>(func);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R>
+Callback<R()> callback(U *obj, R(T::*method)())
+{
+    return Callback<R()>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R>
+Callback<R()> callback(const U *obj, R(T::*method)() const)
+{
+    return Callback<R()>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R>
+Callback<R()> callback(volatile U *obj, R(T::*method)() volatile)
+{
+    return Callback<R()>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R>
+Callback<R()> callback(const volatile U *obj, R(T::*method)() const volatile)
+{
+    return Callback<R()>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R>
+Callback<R()> callback(R(*func)(T *), U *arg)
+{
+    return Callback<R()>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R>
+Callback<R()> callback(R(*func)(const T *), const U *arg)
+{
+    return Callback<R()>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R>
+Callback<R()> callback(R(*func)(volatile T *), volatile U *arg)
+{
+    return Callback<R()>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R>
+Callback<R()> callback(R(*func)(const volatile T *), const volatile U *arg)
+{
+    return Callback<R()>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R()> callback(U *obj, R(*func)(T *))
+{
+    return Callback<R()>(func, obj);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R()> callback(const U *obj, R(*func)(const T *))
+{
+    return Callback<R()>(func, obj);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R()> callback(volatile U *obj, R(*func)(volatile T *))
+{
+    return Callback<R()>(func, obj);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R()> callback(const volatile U *obj, R(*func)(const volatile T *))
+{
+    return Callback<R()>(func, obj);
+}
+
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @return         Callback with infered type
+ */
+template <typename R, typename A0>
+Callback<R(A0)> callback(R(*func)(A0) = 0)
+{
+    return Callback<R(A0)>(func);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @return         Callback with infered type
+ */
+template <typename R, typename A0>
+Callback<R(A0)> callback(const Callback<R(A0)> &func)
+{
+    return Callback<R(A0)>(func);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R, typename A0>
+Callback<R(A0)> callback(U *obj, R(T::*method)(A0))
+{
+    return Callback<R(A0)>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R, typename A0>
+Callback<R(A0)> callback(const U *obj, R(T::*method)(A0) const)
+{
+    return Callback<R(A0)>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R, typename A0>
+Callback<R(A0)> callback(volatile U *obj, R(T::*method)(A0) volatile)
+{
+    return Callback<R(A0)>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R, typename A0>
+Callback<R(A0)> callback(const volatile U *obj, R(T::*method)(A0) const volatile)
+{
+    return Callback<R(A0)>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R, typename A0>
+Callback<R(A0)> callback(R(*func)(T *, A0), U *arg)
+{
+    return Callback<R(A0)>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R, typename A0>
+Callback<R(A0)> callback(R(*func)(const T *, A0), const U *arg)
+{
+    return Callback<R(A0)>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R, typename A0>
+Callback<R(A0)> callback(R(*func)(volatile T *, A0), volatile U *arg)
+{
+    return Callback<R(A0)>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R, typename A0>
+Callback<R(A0)> callback(R(*func)(const volatile T *, A0), const volatile U *arg)
+{
+    return Callback<R(A0)>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R, typename A0>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R(A0)> callback(U *obj, R(*func)(T *, A0))
+{
+    return Callback<R(A0)>(func, obj);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R, typename A0>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R(A0)> callback(const U *obj, R(*func)(const T *, A0))
+{
+    return Callback<R(A0)>(func, obj);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R, typename A0>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R(A0)> callback(volatile U *obj, R(*func)(volatile T *, A0))
+{
+    return Callback<R(A0)>(func, obj);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R, typename A0>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R(A0)> callback(const volatile U *obj, R(*func)(const volatile T *, A0))
+{
+    return Callback<R(A0)>(func, obj);
+}
+
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @return         Callback with infered type
+ */
+template <typename R, typename A0, typename A1>
+Callback<R(A0, A1)> callback(R(*func)(A0, A1) = 0)
+{
+    return Callback<R(A0, A1)>(func);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @return         Callback with infered type
+ */
+template <typename R, typename A0, typename A1>
+Callback<R(A0, A1)> callback(const Callback<R(A0, A1)> &func)
+{
+    return Callback<R(A0, A1)>(func);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R, typename A0, typename A1>
+Callback<R(A0, A1)> callback(U *obj, R(T::*method)(A0, A1))
+{
+    return Callback<R(A0, A1)>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R, typename A0, typename A1>
+Callback<R(A0, A1)> callback(const U *obj, R(T::*method)(A0, A1) const)
+{
+    return Callback<R(A0, A1)>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R, typename A0, typename A1>
+Callback<R(A0, A1)> callback(volatile U *obj, R(T::*method)(A0, A1) volatile)
+{
+    return Callback<R(A0, A1)>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R, typename A0, typename A1>
+Callback<R(A0, A1)> callback(const volatile U *obj, R(T::*method)(A0, A1) const volatile)
+{
+    return Callback<R(A0, A1)>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R, typename A0, typename A1>
+Callback<R(A0, A1)> callback(R(*func)(T *, A0, A1), U *arg)
+{
+    return Callback<R(A0, A1)>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R, typename A0, typename A1>
+Callback<R(A0, A1)> callback(R(*func)(const T *, A0, A1), const U *arg)
+{
+    return Callback<R(A0, A1)>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R, typename A0, typename A1>
+Callback<R(A0, A1)> callback(R(*func)(volatile T *, A0, A1), volatile U *arg)
+{
+    return Callback<R(A0, A1)>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R, typename A0, typename A1>
+Callback<R(A0, A1)> callback(R(*func)(const volatile T *, A0, A1), const volatile U *arg)
+{
+    return Callback<R(A0, A1)>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R, typename A0, typename A1>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R(A0, A1)> callback(U *obj, R(*func)(T *, A0, A1))
+{
+    return Callback<R(A0, A1)>(func, obj);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R, typename A0, typename A1>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R(A0, A1)> callback(const U *obj, R(*func)(const T *, A0, A1))
+{
+    return Callback<R(A0, A1)>(func, obj);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R, typename A0, typename A1>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R(A0, A1)> callback(volatile U *obj, R(*func)(volatile T *, A0, A1))
+{
+    return Callback<R(A0, A1)>(func, obj);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R, typename A0, typename A1>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R(A0, A1)> callback(const volatile U *obj, R(*func)(const volatile T *, A0, A1))
+{
+    return Callback<R(A0, A1)>(func, obj);
+}
+
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @return         Callback with infered type
+ */
+template <typename R, typename A0, typename A1, typename A2>
+Callback<R(A0, A1, A2)> callback(R(*func)(A0, A1, A2) = 0)
+{
+    return Callback<R(A0, A1, A2)>(func);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @return         Callback with infered type
+ */
+template <typename R, typename A0, typename A1, typename A2>
+Callback<R(A0, A1, A2)> callback(const Callback<R(A0, A1, A2)> &func)
+{
+    return Callback<R(A0, A1, A2)>(func);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R, typename A0, typename A1, typename A2>
+Callback<R(A0, A1, A2)> callback(U *obj, R(T::*method)(A0, A1, A2))
+{
+    return Callback<R(A0, A1, A2)>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R, typename A0, typename A1, typename A2>
+Callback<R(A0, A1, A2)> callback(const U *obj, R(T::*method)(A0, A1, A2) const)
+{
+    return Callback<R(A0, A1, A2)>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R, typename A0, typename A1, typename A2>
+Callback<R(A0, A1, A2)> callback(volatile U *obj, R(T::*method)(A0, A1, A2) volatile)
+{
+    return Callback<R(A0, A1, A2)>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R, typename A0, typename A1, typename A2>
+Callback<R(A0, A1, A2)> callback(const volatile U *obj, R(T::*method)(A0, A1, A2) const volatile)
+{
+    return Callback<R(A0, A1, A2)>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2>
+Callback<R(A0, A1, A2)> callback(R(*func)(T *, A0, A1, A2), U *arg)
+{
+    return Callback<R(A0, A1, A2)>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2>
+Callback<R(A0, A1, A2)> callback(R(*func)(const T *, A0, A1, A2), const U *arg)
+{
+    return Callback<R(A0, A1, A2)>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2>
+Callback<R(A0, A1, A2)> callback(R(*func)(volatile T *, A0, A1, A2), volatile U *arg)
+{
+    return Callback<R(A0, A1, A2)>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2>
+Callback<R(A0, A1, A2)> callback(R(*func)(const volatile T *, A0, A1, A2), const volatile U *arg)
+{
+    return Callback<R(A0, A1, A2)>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R(A0, A1, A2)> callback(U *obj, R(*func)(T *, A0, A1, A2))
+{
+    return Callback<R(A0, A1, A2)>(func, obj);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R(A0, A1, A2)> callback(const U *obj, R(*func)(const T *, A0, A1, A2))
+{
+    return Callback<R(A0, A1, A2)>(func, obj);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R(A0, A1, A2)> callback(volatile U *obj, R(*func)(volatile T *, A0, A1, A2))
+{
+    return Callback<R(A0, A1, A2)>(func, obj);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R(A0, A1, A2)> callback(const volatile U *obj, R(*func)(const volatile T *, A0, A1, A2))
+{
+    return Callback<R(A0, A1, A2)>(func, obj);
+}
+
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @return         Callback with infered type
+ */
+template <typename R, typename A0, typename A1, typename A2, typename A3>
+Callback<R(A0, A1, A2, A3)> callback(R(*func)(A0, A1, A2, A3) = 0)
+{
+    return Callback<R(A0, A1, A2, A3)>(func);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @return         Callback with infered type
+ */
+template <typename R, typename A0, typename A1, typename A2, typename A3>
+Callback<R(A0, A1, A2, A3)> callback(const Callback<R(A0, A1, A2, A3)> &func)
+{
+    return Callback<R(A0, A1, A2, A3)>(func);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3>
+Callback<R(A0, A1, A2, A3)> callback(U *obj, R(T::*method)(A0, A1, A2, A3))
+{
+    return Callback<R(A0, A1, A2, A3)>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3>
+Callback<R(A0, A1, A2, A3)> callback(const U *obj, R(T::*method)(A0, A1, A2, A3) const)
+{
+    return Callback<R(A0, A1, A2, A3)>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3>
+Callback<R(A0, A1, A2, A3)> callback(volatile U *obj, R(T::*method)(A0, A1, A2, A3) volatile)
+{
+    return Callback<R(A0, A1, A2, A3)>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3>
+Callback<R(A0, A1, A2, A3)> callback(const volatile U *obj, R(T::*method)(A0, A1, A2, A3) const volatile)
+{
+    return Callback<R(A0, A1, A2, A3)>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3>
+Callback<R(A0, A1, A2, A3)> callback(R(*func)(T *, A0, A1, A2, A3), U *arg)
+{
+    return Callback<R(A0, A1, A2, A3)>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3>
+Callback<R(A0, A1, A2, A3)> callback(R(*func)(const T *, A0, A1, A2, A3), const U *arg)
+{
+    return Callback<R(A0, A1, A2, A3)>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3>
+Callback<R(A0, A1, A2, A3)> callback(R(*func)(volatile T *, A0, A1, A2, A3), volatile U *arg)
+{
+    return Callback<R(A0, A1, A2, A3)>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3>
+Callback<R(A0, A1, A2, A3)> callback(R(*func)(const volatile T *, A0, A1, A2, A3), const volatile U *arg)
+{
+    return Callback<R(A0, A1, A2, A3)>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R(A0, A1, A2, A3)> callback(U *obj, R(*func)(T *, A0, A1, A2, A3))
+{
+    return Callback<R(A0, A1, A2, A3)>(func, obj);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R(A0, A1, A2, A3)> callback(const U *obj, R(*func)(const T *, A0, A1, A2, A3))
+{
+    return Callback<R(A0, A1, A2, A3)>(func, obj);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R(A0, A1, A2, A3)> callback(volatile U *obj, R(*func)(volatile T *, A0, A1, A2, A3))
+{
+    return Callback<R(A0, A1, A2, A3)>(func, obj);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R(A0, A1, A2, A3)> callback(const volatile U *obj, R(*func)(const volatile T *, A0, A1, A2, A3))
+{
+    return Callback<R(A0, A1, A2, A3)>(func, obj);
+}
+
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @return         Callback with infered type
+ */
+template <typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+Callback<R(A0, A1, A2, A3, A4)> callback(R(*func)(A0, A1, A2, A3, A4) = 0)
+{
+    return Callback<R(A0, A1, A2, A3, A4)>(func);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @return         Callback with infered type
+ */
+template <typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+Callback<R(A0, A1, A2, A3, A4)> callback(const Callback<R(A0, A1, A2, A3, A4)> &func)
+{
+    return Callback<R(A0, A1, A2, A3, A4)>(func);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+Callback<R(A0, A1, A2, A3, A4)> callback(U *obj, R(T::*method)(A0, A1, A2, A3, A4))
+{
+    return Callback<R(A0, A1, A2, A3, A4)>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+Callback<R(A0, A1, A2, A3, A4)> callback(const U *obj, R(T::*method)(A0, A1, A2, A3, A4) const)
+{
+    return Callback<R(A0, A1, A2, A3, A4)>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+Callback<R(A0, A1, A2, A3, A4)> callback(volatile U *obj, R(T::*method)(A0, A1, A2, A3, A4) volatile)
+{
+    return Callback<R(A0, A1, A2, A3, A4)>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj      Optional pointer to object to bind to function
+ *  @param method   Member function to attach
+ *  @return         Callback with infered type
+ */
+template<typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+Callback<R(A0, A1, A2, A3, A4)> callback(const volatile U *obj, R(T::*method)(A0, A1, A2, A3, A4) const volatile)
+{
+    return Callback<R(A0, A1, A2, A3, A4)>(obj, method);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+Callback<R(A0, A1, A2, A3, A4)> callback(R(*func)(T *, A0, A1, A2, A3, A4), U *arg)
+{
+    return Callback<R(A0, A1, A2, A3, A4)>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+Callback<R(A0, A1, A2, A3, A4)> callback(R(*func)(const T *, A0, A1, A2, A3, A4), const U *arg)
+{
+    return Callback<R(A0, A1, A2, A3, A4)>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+Callback<R(A0, A1, A2, A3, A4)> callback(R(*func)(volatile T *, A0, A1, A2, A3, A4), volatile U *arg)
+{
+    return Callback<R(A0, A1, A2, A3, A4)>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func     Static function to attach
+ *  @param arg      Pointer argument to function
+ *  @return         Callback with infered type
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+Callback<R(A0, A1, A2, A3, A4)> callback(R(*func)(const volatile T *, A0, A1, A2, A3, A4), const volatile U *arg)
+{
+    return Callback<R(A0, A1, A2, A3, A4)>(func, arg);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R(A0, A1, A2, A3, A4)> callback(U *obj, R(*func)(T *, A0, A1, A2, A3, A4))
+{
+    return Callback<R(A0, A1, A2, A3, A4)>(func, obj);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R(A0, A1, A2, A3, A4)> callback(const U *obj, R(*func)(const T *, A0, A1, A2, A3, A4))
+{
+    return Callback<R(A0, A1, A2, A3, A4)>(func, obj);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R(A0, A1, A2, A3, A4)> callback(volatile U *obj, R(*func)(volatile T *, A0, A1, A2, A3, A4))
+{
+    return Callback<R(A0, A1, A2, A3, A4)>(func, obj);
+}
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ *  @deprecated
+ *      Arguments to callback have been reordered to callback(func, arg)
+ */
+template <typename T, typename U, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+MBED_DEPRECATED_SINCE("mbed-os-5.1",
+                      "Arguments to callback have been reordered to callback(func, arg)")
+Callback<R(A0, A1, A2, A3, A4)> callback(const volatile U *obj, R(*func)(const volatile T *, A0, A1, A2, A3, A4))
+{
+    return Callback<R(A0, A1, A2, A3, A4)>(func, obj);
+}
+
+/**@}*/
+
+/**@}*/
+
+} // namespace mbed
+
+#endif