atomic_signal_fence()

Arguments:

order

The memory_order to use for the fence.

Library:

• If the atomic function is lock-free (see atomic_is_lock_free()), no extra library is required.
• If the function isn't lock-free, you need to link against libatomic. Use the -l atomic option to qcc to link against this library.

Description:

The atomic_signal_fence() function establishes a memory-synchronization ordering of non-atomic and relaxed atomic accesses, as instructed by order, between a thread and a signal handler executed on the same thread. Only reordering of the instructions by the compiler is suppressed as order instructs. For example, writes can't be moved past a fence with release semantics, and reads can't be moved ahead of a fence with acquire semantics.

The implementation of atomic functions may depend on the architecture. For more information, see “LL/SC vs LSE atomic operations” in the description in Building Embedded Systems of the cpuinfo area of the system page.

Classification:

C11

Caveats:

If this function is lock-free (see atomic_is_lock_free()), it's safe to call it from an ISR or signal handler.