ARM Compiler ARM C and C++ Libraries and Floating-Point Support User Guide : 1.7.12 Standard library concurrency constructs [ALPHA]

1.7.12 Standard library concurrency constructs [ALPHA]

The C++ standard library, beginning with the C++11 standard, provides various high-level concurrency constructs. Presently, these constructs are spread across the headers <atomic>, <chrono>, <mutex>, <shared_mutex>, <condition_variable>, <thread>, and <future>.

Note:

This topic describes an [ALPHA] feature. See Support level definitions.

The following sections identify how the functionality of each of these headers maps to the ARM Compiler thread porting API introduced in 1.7.1 ARM C++ libraries and multithreading [ALPHA]. They also identify any additional dependencies or expected limitations.

<atomic>

The functionality of this header does not depend on the thread porting API.

The following table summarizes the level of support for the <atomic> header on various ARM architectures.

Architecture	`T` (Template parameter)	`atomic<T>`	`atomic<T*>`
ARMv7A/R, ARMv8A/R	Any types	Supported	Supported
ARMv7M, ARMv8M	Integral types (including `<stdint.h>` defined types)	Supported	Supported
ARMv7M, ARMv8M	Complex types	Unsupported	Supported
ARMv6M	Any types	Unsupported	Unsupported

None of the targets support the functions atomic_thread_fence() and atomic_signal_fence().

<chrono>

This header requires a full implementation of the 1.7.2 Clocks [ALPHA] section of the thread porting API.

<mutex>, <shared_mutex>

These headers require a full implementation of the 1.7.3 Mutexes [ALPHA] section of the thread porting API. In addition, the time-related subset of constructs (for example, std::timed_mutex and std::recursive_timed_mutex) defined in these headers requires an implementation of the 1.7.2 Clocks [ALPHA] section of the porting API.

<condition_variable>

This header requires a full implementation of the 1.7.4 Condition variables [ALPHA] section of the thread porting API. In addition, the time-related subset of constructs (for example, std::condition_variable::wait_for()) defined in this header requires an implementation of the 1.7.2 Clocks [ALPHA] section of the porting API.

<thread>, <future>

These headers require a full implementation of the 1.7.5 Threads [ALPHA] section of the thread porting API. In addition, the time-related subset of constructs (for example, std::thread::sleep_until() and std::future::wait_for()) defined in these headers requires an implementation of the 1.7.2 Clocks [ALPHA] section of the porting API.

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