Diff: mbed-os/platform/Callback.h

Revision:

0:fbdae7e6d805

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-os/platform/Callback.h	Mon May 14 11:29:06 2018 +0000
@@ -0,0 +1,4552 @@
+/* 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