Initializer for a core_util_atomic_flag.

Example:

Definition at line 127 of file mbed_atomic.h.

A lock-free, primitive atomic flag.

Emulate C11's atomic_flag. The flag is initially in an indeterminate state unless explicitly initialized with CORE_UTIL_ATOMIC_FLAG_INIT.

Memory order constraints for atomic operations.

Intended semantics are as per C++11.

Memory order constraints for atomic operations.

Intended semantics are as per C++11.

Definition at line 51 of file mbed_atomic.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = atomic_load(p) while not done { done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success } return value + a }

However, if the call is made in a loop like this, the atomic_compare_exchange_weak functions are to be preferred.

Note

: This corresponds to the C11 "atomic_compare_exchange_strong" - it always succeeds if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return does not retry.

Definition at line 768 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = atomic_load(p) while not done { done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success } return value + a }

However, if the call is made in a loop like this, the atomic_compare_exchange_weak functions are to be preferred.

Note

: This corresponds to the C11 "atomic_compare_exchange_strong" - it always succeeds if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return does not retry.

Parameters

success	memory ordering constraint for successful exchange
failure	memory ordering constraint for failure

Definition at line 773 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = atomic_load(p) while not done { done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success } return value + a }

However, if the call is made in a loop like this, the atomic_compare_exchange_weak functions are to be preferred.

Note

: This corresponds to the C11 "atomic_compare_exchange_strong" - it always succeeds if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return does not retry.

Parameters

success	memory ordering constraint for successful exchange
failure	memory ordering constraint for failure

Definition at line 793 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = atomic_load(p) while not done { done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success } return value + a }

However, if the call is made in a loop like this, the atomic_compare_exchange_weak functions are to be preferred.

Note

: This corresponds to the C11 "atomic_compare_exchange_strong" - it always succeeds if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return does not retry.

Parameters

success	memory ordering constraint for successful exchange
failure	memory ordering constraint for failure

Definition at line 765 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = atomic_load(p) while not done { done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success } return value + a }

However, if the call is made in a loop like this, the atomic_compare_exchange_weak functions are to be preferred.

Note

: This corresponds to the C11 "atomic_compare_exchange_strong" - it always succeeds if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return does not retry.

Parameters

success	memory ordering constraint for successful exchange
failure	memory ordering constraint for failure

Definition at line 765 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = atomic_load(p) while not done { done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success } return value + a }

However, if the call is made in a loop like this, the atomic_compare_exchange_weak functions are to be preferred.

Note

: This corresponds to the C11 "atomic_compare_exchange_strong" - it always succeeds if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return does not retry.

Parameters

success	memory ordering constraint for successful exchange
failure	memory ordering constraint for failure

Definition at line 765 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = atomic_load(p) while not done { done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success } return value + a }

However, if the call is made in a loop like this, the atomic_compare_exchange_weak functions are to be preferred.

Note

: This corresponds to the C11 "atomic_compare_exchange_strong" - it always succeeds if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return does not retry.

Parameters

success	memory ordering constraint for successful exchange
failure	memory ordering constraint for failure

Definition at line 765 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = atomic_load(p) while not done { done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success } return value + a }

However, if the call is made in a loop like this, the atomic_compare_exchange_weak functions are to be preferred.

Note

: This corresponds to the C11 "atomic_compare_exchange_strong" - it always succeeds if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return does not retry.

Parameters

success	memory ordering constraint for successful exchange
failure	memory ordering constraint for failure

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = atomic_load(p) while not done { done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success } return value + a }

However, if the call is made in a loop like this, the atomic_compare_exchange_weak functions are to be preferred.

Note

: This corresponds to the C11 "atomic_compare_exchange_strong" - it always succeeds if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return does not retry.

Parameters

success	memory ordering constraint for successful exchange
failure	memory ordering constraint for failure

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = atomic_load(p) while not done { done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success } return value + a }

However, if the call is made in a loop like this, the atomic_compare_exchange_weak functions are to be preferred.

Note

: This corresponds to the C11 "atomic_compare_exchange_strong" - it always succeeds if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return does not retry.

Parameters

success	memory ordering constraint for successful exchange
failure	memory ordering constraint for failure

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = atomic_load(p) while not done { done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success } return value + a }

However, if the call is made in a loop like this, the atomic_compare_exchange_weak functions are to be preferred.

Note

: This corresponds to the C11 "atomic_compare_exchange_strong" - it always succeeds if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return does not retry.

Parameters

success	memory ordering constraint for successful exchange
failure	memory ordering constraint for failure

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = atomic_load(p) while not done { done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success } return value + a }

However, if the call is made in a loop like this, the atomic_compare_exchange_weak functions are to be preferred.

Note

: This corresponds to the C11 "atomic_compare_exchange_strong" - it always succeeds if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return does not retry.

Definition at line 778 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = atomic_load(p) while not done { done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success } return value + a }

However, if the call is made in a loop like this, the atomic_compare_exchange_weak functions are to be preferred.

Note

: This corresponds to the C11 "atomic_compare_exchange_strong" - it always succeeds if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return does not retry.

Definition at line 765 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = atomic_load(p) while not done { done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success } return value + a }

However, if the call is made in a loop like this, the atomic_compare_exchange_weak functions are to be preferred.

Note

: This corresponds to the C11 "atomic_compare_exchange_strong" - it always succeeds if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return does not retry.

Definition at line 765 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = atomic_load(p) while not done { done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success } return value + a }

However, if the call is made in a loop like this, the atomic_compare_exchange_weak functions are to be preferred.

Note

: This corresponds to the C11 "atomic_compare_exchange_strong" - it always succeeds if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return does not retry.

Definition at line 765 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = atomic_load(p) while not done { done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success } return value + a }

However, if the call is made in a loop like this, the atomic_compare_exchange_weak functions are to be preferred.

Note

: This corresponds to the C11 "atomic_compare_exchange_strong" - it always succeeds if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return does not retry.

Definition at line 765 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = atomic_load(p) while not done { done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success } return value + a }

However, if the call is made in a loop like this, the atomic_compare_exchange_weak functions are to be preferred.

Note

: This corresponds to the C11 "atomic_compare_exchange_strong" - it always succeeds if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return does not retry.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = atomic_load(p) while not done { done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success } return value + a }

However, if the call is made in a loop like this, the atomic_compare_exchange_weak functions are to be preferred.

Note

: This corresponds to the C11 "atomic_compare_exchange_strong" - it always succeeds if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return does not retry.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = atomic_load(p) while not done { done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success } return value + a }

However, if the call is made in a loop like this, the atomic_compare_exchange_weak functions are to be preferred.

Note

: This corresponds to the C11 "atomic_compare_exchange_strong" - it always succeeds if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return does not retry.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = atomic_load(p) while not done { done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success } return value + a }

However, if the call is made in a loop like this, the atomic_compare_exchange_weak functions are to be preferred.

Note

: This corresponds to the C11 "atomic_compare_exchange_strong" - it always succeeds if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return does not retry.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old or spurious failure { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = *p // This fetch operation need not be atomic. while not done { done = atomic_compare_exchange_weak(p, &value, value + a) // *value gets updated automatically until success } return value + a }

Note

: This corresponds to the C11 "atomic_compare_exchange_weak" - it may spuriously fail if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return will cause a retry anyway, saving the need for an extra loop inside the cas operation.

Definition at line 810 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old or spurious failure { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = *p // This fetch operation need not be atomic. while not done { done = atomic_compare_exchange_weak(p, &value, value + a) // *value gets updated automatically until success } return value + a }

Note

: This corresponds to the C11 "atomic_compare_exchange_weak" - it may spuriously fail if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return will cause a retry anyway, saving the need for an extra loop inside the cas operation.

Parameters

success	memory ordering constraint for successful exchange
failure	memory ordering constraint for failure

Definition at line 815 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old or spurious failure { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = *p // This fetch operation need not be atomic. while not done { done = atomic_compare_exchange_weak(p, &value, value + a) // *value gets updated automatically until success } return value + a }

Note

: This corresponds to the C11 "atomic_compare_exchange_weak" - it may spuriously fail if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return will cause a retry anyway, saving the need for an extra loop inside the cas operation.

Parameters

success	memory ordering constraint for successful exchange
failure	memory ordering constraint for failure

Definition at line 835 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old or spurious failure { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = *p // This fetch operation need not be atomic. while not done { done = atomic_compare_exchange_weak(p, &value, value + a) // *value gets updated automatically until success } return value + a }

Note

: This corresponds to the C11 "atomic_compare_exchange_weak" - it may spuriously fail if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return will cause a retry anyway, saving the need for an extra loop inside the cas operation.

Parameters

success	memory ordering constraint for successful exchange
failure	memory ordering constraint for failure

Definition at line 766 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old or spurious failure { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = *p // This fetch operation need not be atomic. while not done { done = atomic_compare_exchange_weak(p, &value, value + a) // *value gets updated automatically until success } return value + a }

Note

: This corresponds to the C11 "atomic_compare_exchange_weak" - it may spuriously fail if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return will cause a retry anyway, saving the need for an extra loop inside the cas operation.

Parameters

success	memory ordering constraint for successful exchange
failure	memory ordering constraint for failure

Definition at line 766 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old or spurious failure { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = *p // This fetch operation need not be atomic. while not done { done = atomic_compare_exchange_weak(p, &value, value + a) // *value gets updated automatically until success } return value + a }

Note

: This corresponds to the C11 "atomic_compare_exchange_weak" - it may spuriously fail if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return will cause a retry anyway, saving the need for an extra loop inside the cas operation.

Parameters

success	memory ordering constraint for successful exchange
failure	memory ordering constraint for failure

Definition at line 766 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old or spurious failure { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = *p // This fetch operation need not be atomic. while not done { done = atomic_compare_exchange_weak(p, &value, value + a) // *value gets updated automatically until success } return value + a }

Note

: This corresponds to the C11 "atomic_compare_exchange_weak" - it may spuriously fail if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return will cause a retry anyway, saving the need for an extra loop inside the cas operation.

Parameters

success	memory ordering constraint for successful exchange
failure	memory ordering constraint for failure

Definition at line 766 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old or spurious failure { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = *p // This fetch operation need not be atomic. while not done { done = atomic_compare_exchange_weak(p, &value, value + a) // *value gets updated automatically until success } return value + a }

Note

: This corresponds to the C11 "atomic_compare_exchange_weak" - it may spuriously fail if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return will cause a retry anyway, saving the need for an extra loop inside the cas operation.

Parameters

success	memory ordering constraint for successful exchange
failure	memory ordering constraint for failure

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old or spurious failure { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = *p // This fetch operation need not be atomic. while not done { done = atomic_compare_exchange_weak(p, &value, value + a) // *value gets updated automatically until success } return value + a }

Note

: This corresponds to the C11 "atomic_compare_exchange_weak" - it may spuriously fail if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return will cause a retry anyway, saving the need for an extra loop inside the cas operation.

Parameters

success	memory ordering constraint for successful exchange
failure	memory ordering constraint for failure

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old or spurious failure { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = *p // This fetch operation need not be atomic. while not done { done = atomic_compare_exchange_weak(p, &value, value + a) // *value gets updated automatically until success } return value + a }

Note

: This corresponds to the C11 "atomic_compare_exchange_weak" - it may spuriously fail if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return will cause a retry anyway, saving the need for an extra loop inside the cas operation.

Parameters

success	memory ordering constraint for successful exchange
failure	memory ordering constraint for failure

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old or spurious failure { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = *p // This fetch operation need not be atomic. while not done { done = atomic_compare_exchange_weak(p, &value, value + a) // *value gets updated automatically until success } return value + a }

Note

: This corresponds to the C11 "atomic_compare_exchange_weak" - it may spuriously fail if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return will cause a retry anyway, saving the need for an extra loop inside the cas operation.

Parameters

success	memory ordering constraint for successful exchange
failure	memory ordering constraint for failure

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old or spurious failure { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = *p // This fetch operation need not be atomic. while not done { done = atomic_compare_exchange_weak(p, &value, value + a) // *value gets updated automatically until success } return value + a }

Note

: This corresponds to the C11 "atomic_compare_exchange_weak" - it may spuriously fail if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return will cause a retry anyway, saving the need for an extra loop inside the cas operation.

Definition at line 820 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old or spurious failure { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = *p // This fetch operation need not be atomic. while not done { done = atomic_compare_exchange_weak(p, &value, value + a) // *value gets updated automatically until success } return value + a }

Note

: This corresponds to the C11 "atomic_compare_exchange_weak" - it may spuriously fail if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return will cause a retry anyway, saving the need for an extra loop inside the cas operation.

Definition at line 766 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old or spurious failure { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = *p // This fetch operation need not be atomic. while not done { done = atomic_compare_exchange_weak(p, &value, value + a) // *value gets updated automatically until success } return value + a }

Note

: This corresponds to the C11 "atomic_compare_exchange_weak" - it may spuriously fail if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return will cause a retry anyway, saving the need for an extra loop inside the cas operation.

Definition at line 766 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old or spurious failure { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = *p // This fetch operation need not be atomic. while not done { done = atomic_compare_exchange_weak(p, &value, value + a) // *value gets updated automatically until success } return value + a }

Note

: This corresponds to the C11 "atomic_compare_exchange_weak" - it may spuriously fail if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return will cause a retry anyway, saving the need for an extra loop inside the cas operation.

Definition at line 766 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old or spurious failure { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = *p // This fetch operation need not be atomic. while not done { done = atomic_compare_exchange_weak(p, &value, value + a) // *value gets updated automatically until success } return value + a }

Note

: This corresponds to the C11 "atomic_compare_exchange_weak" - it may spuriously fail if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return will cause a retry anyway, saving the need for an extra loop inside the cas operation.

Definition at line 766 of file mbed_atomic_impl.h.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old or spurious failure { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = *p // This fetch operation need not be atomic. while not done { done = atomic_compare_exchange_weak(p, &value, value + a) // *value gets updated automatically until success } return value + a }

Note

: This corresponds to the C11 "atomic_compare_exchange_weak" - it may spuriously fail if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return will cause a retry anyway, saving the need for an extra loop inside the cas operation.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old or spurious failure { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = *p // This fetch operation need not be atomic. while not done { done = atomic_compare_exchange_weak(p, &value, value + a) // *value gets updated automatically until success } return value + a }

Note

: This corresponds to the C11 "atomic_compare_exchange_weak" - it may spuriously fail if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return will cause a retry anyway, saving the need for an extra loop inside the cas operation.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old or spurious failure { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = *p // This fetch operation need not be atomic. while not done { done = atomic_compare_exchange_weak(p, &value, value + a) // *value gets updated automatically until success } return value + a }

Note

: This corresponds to the C11 "atomic_compare_exchange_weak" - it may spuriously fail if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return will cause a retry anyway, saving the need for an extra loop inside the cas operation.

Atomic compare and set.

It compares the contents of a memory location to a given value and, only if they are the same, modifies the contents of that memory location to a given new value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail due to a mismatched expectedCurrentValue.

Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect you to the article on compare-and swap].

Parameters

	ptr	The target memory location.
[in,out]	expectedCurrentValue	A pointer to some location holding the expected current value of the data being set atomically. The computed 'desiredValue' should be a function of this current value.

Note

: This is an in-out parameter. In the failure case of atomic_cas (where the destination isn't set), the pointee of expectedCurrentValue is updated with the current value.

Parameters

[in]

desiredValue

The new value computed based on '*expectedCurrentValue'.

Returns

true if the memory location was atomically updated with the desired value (after verifying that it contained the expectedCurrentValue), false otherwise. In the failure case, exepctedCurrentValue is updated with the new value of the target memory location.

pseudocode: function cas(p : pointer to int, old : pointer to int, new : int) returns bool { if *p != *old or spurious failure { *old = *p return false } *p = new return true }

Note

: In the failure case (where the destination isn't set), the value pointed to by expectedCurrentValue is instead updated with the current value. This property helps writing concise code for the following incr:

function incr(p : pointer to int, a : int) returns int { done = false value = *p // This fetch operation need not be atomic. while not done { done = atomic_compare_exchange_weak(p, &value, value + a) // *value gets updated automatically until success } return value + a }

Note

: This corresponds to the C11 "atomic_compare_exchange_weak" - it may spuriously fail if the current value is expected, as per the pseudocode above; it will not spuriously fail as "atomic_compare_exchange_weak" may. This call would normally be used when a fail return will cause a retry anyway, saving the need for an extra loop inside the cas operation.

Atomic decrement.

Parameters

valuePtr	Target memory location being decremented.
delta	The amount being decremented.

Returns

The new decremented value.

Definition at line 923 of file mbed_atomic_impl.h.

Atomic decrement.

Parameters

valuePtr	Target memory location being decremented.
delta	The amount being decremented.

Returns

The new decremented value.

Definition at line 878 of file mbed_atomic_impl.h.

Atomic decrement.

Parameters

valuePtr	Target memory location being decremented.
delta	The amount being decremented.

Returns

The new decremented value.

Definition at line 878 of file mbed_atomic_impl.h.

Atomic decrement.

Parameters

valuePtr	Target memory location being decremented.
delta	The amount being decremented.

Returns

The new decremented value.

Definition at line 878 of file mbed_atomic_impl.h.

Atomic decrement.

Parameters

valuePtr	Target memory location being decremented.
delta	The amount being decremented.

Returns

The new decremented value.

Definition at line 878 of file mbed_atomic_impl.h.

Atomic decrement.

Parameters

valuePtr	Target memory location being decremented.
delta	The amount being decremented.

Returns

The new decremented value.

Atomic decrement.

Parameters

valuePtr	Target memory location being decremented.
delta	The amount being decremented.

Returns

The new decremented value.

Atomic decrement.

Parameters

valuePtr	Target memory location being decremented.
delta	The amount being decremented.

Returns

The new decremented value.

Atomic decrement.

Parameters

valuePtr	Target memory location being decremented.
delta	The amount being decremented.

Returns

The new decremented value.

Atomic exchange.

Parameters

valuePtr	Target memory location.
desiredValue	The value to store.

Returns

The previous value.

Definition at line 886 of file mbed_atomic_impl.h.

Atomic exchange.

Parameters

valuePtr	Target memory location.
desiredValue	The value to store.

Returns

The previous value.

Parameters

order

memory ordering constraint

Definition at line 891 of file mbed_atomic_impl.h.

Atomic exchange.

Parameters

valuePtr	Target memory location.
desiredValue	The value to store.

Returns

The previous value.

Parameters

order

memory ordering constraint

Definition at line 905 of file mbed_atomic_impl.h.

Atomic exchange.

Parameters

valuePtr	Target memory location.
desiredValue	The value to store.

Returns

The previous value.

Parameters

order

memory ordering constraint

Definition at line 882 of file mbed_atomic_impl.h.

Atomic exchange.

Parameters

valuePtr	Target memory location.
desiredValue	The value to store.

Returns

The previous value.

Parameters

order

memory ordering constraint

Definition at line 882 of file mbed_atomic_impl.h.

Atomic exchange.

Parameters

valuePtr	Target memory location.
desiredValue	The value to store.

Returns

The previous value.

Parameters

order

memory ordering constraint

Definition at line 882 of file mbed_atomic_impl.h.

Atomic exchange.

Parameters

valuePtr	Target memory location.
desiredValue	The value to store.

Returns

The previous value.

Parameters

order

memory ordering constraint

Definition at line 882 of file mbed_atomic_impl.h.

Atomic exchange.

Parameters

valuePtr	Target memory location.
desiredValue	The value to store.

Returns

The previous value.

Parameters

order

memory ordering constraint

Atomic exchange.

Parameters

valuePtr	Target memory location.
desiredValue	The value to store.

Returns

The previous value.

Parameters

order

memory ordering constraint

Atomic exchange.

Parameters

valuePtr	Target memory location.
desiredValue	The value to store.

Returns

The previous value.

Parameters

order

memory ordering constraint

Atomic exchange.

Parameters

valuePtr	Target memory location.
desiredValue	The value to store.

Returns

The previous value.

Parameters

order

memory ordering constraint

Atomic exchange.

Parameters

valuePtr	Target memory location.
desiredValue	The value to store.

Returns

The previous value.

Definition at line 896 of file mbed_atomic_impl.h.

Atomic exchange.

Parameters

valuePtr	Target memory location.
desiredValue	The value to store.

Returns

The previous value.

Definition at line 876 of file mbed_atomic_impl.h.

Atomic exchange.

Parameters

valuePtr	Target memory location.
desiredValue	The value to store.

Returns

The previous value.

Definition at line 876 of file mbed_atomic_impl.h.

Atomic exchange.

Parameters

valuePtr	Target memory location.
desiredValue	The value to store.

Returns

The previous value.

Definition at line 876 of file mbed_atomic_impl.h.

Atomic exchange.

Parameters

valuePtr	Target memory location.
desiredValue	The value to store.

Returns

The previous value.

Definition at line 876 of file mbed_atomic_impl.h.

Atomic exchange.

Parameters

valuePtr	Target memory location.
desiredValue	The value to store.

Returns

The previous value.

Atomic exchange.

Parameters

valuePtr	Target memory location.
desiredValue	The value to store.

Returns

The previous value.

Atomic exchange.

Parameters

valuePtr	Target memory location.
desiredValue	The value to store.

Returns

The previous value.

Atomic exchange.

Parameters

valuePtr	Target memory location.
desiredValue	The value to store.

Returns

The previous value.

Atomic add.

Parameters

valuePtr	Target memory location being modified.
arg	The argument for the addition.

Returns

The original value.

Parameters

order

memory ordering constraint

Definition at line 941 of file mbed_atomic_impl.h.

Atomic add.

Parameters

valuePtr	Target memory location being modified.
arg	The argument for the addition.

Returns

The original value.

Parameters

order

memory ordering constraint

Definition at line 883 of file mbed_atomic_impl.h.

Atomic add.

Parameters

valuePtr	Target memory location being modified.
arg	The argument for the addition.

Returns

The original value.

Parameters

order

memory ordering constraint

Definition at line 883 of file mbed_atomic_impl.h.

Atomic add.

Parameters

valuePtr	Target memory location being modified.
arg	The argument for the addition.

Returns

The original value.

Parameters

order

memory ordering constraint

Definition at line 883 of file mbed_atomic_impl.h.

Atomic add.

Parameters

valuePtr	Target memory location being modified.
arg	The argument for the addition.

Returns

The original value.

Parameters

order

memory ordering constraint

Definition at line 883 of file mbed_atomic_impl.h.

Atomic add.

Parameters

valuePtr	Target memory location being modified.
arg	The argument for the addition.

Returns

The original value.

Parameters

order

memory ordering constraint

Atomic add.

Parameters

valuePtr	Target memory location being modified.
arg	The argument for the addition.

Returns

The original value.

Parameters

order

memory ordering constraint

Atomic add.

Parameters

valuePtr	Target memory location being modified.
arg	The argument for the addition.

Returns

The original value.

Parameters

order

memory ordering constraint

Atomic add.

Parameters

valuePtr	Target memory location being modified.
arg	The argument for the addition.

Returns

The original value.

Parameters

order

memory ordering constraint

Atomic add.

Parameters

valuePtr	Target memory location being modified.
arg	The argument for the addition.

Returns

The original value.

Definition at line 932 of file mbed_atomic_impl.h.

Atomic add.

Parameters

valuePtr	Target memory location being modified.
arg	The argument for the addition.

Returns

The original value.

Definition at line 879 of file mbed_atomic_impl.h.

Atomic add.

Parameters

valuePtr	Target memory location being modified.
arg	The argument for the addition.

Returns

The original value.

Definition at line 879 of file mbed_atomic_impl.h.

Atomic add.

Parameters

valuePtr	Target memory location being modified.
arg	The argument for the addition.

Returns

The original value.

Definition at line 879 of file mbed_atomic_impl.h.

Atomic add.

Parameters

valuePtr	Target memory location being modified.
arg	The argument for the addition.