ATOMIC_SWAP(3) Library Functions Manual ATOMIC_SWAP(3)
atomic_swap, atomic_swap_32, atomic_swap_uint, atomic_swap_ulong,
atomic_swap_ptr, atomic_swap_64 -- atomic swap operations
atomic_swap_32(volatile uint32_t *ptr, uint32_t new);
atomic_swap_uint(volatile unsigned int *ptr, unsigned int new);
atomic_swap_ulong(volatile unsigned long *ptr, unsigned long new);
atomic_swap_ptr(volatile void *ptr, void *new);
atomic_swap_64(volatile uint64_t *ptr, uint64_t new);
The atomic_swap family of functions perform a swap operation in an atomic
fashion. The value of the variable referenced by ptr is replaced by new
and the old value returned.
The 64-bit variants of these functions are available only on platforms
that can support atomic 64-bit memory access. Applications can check for
the availability of 64-bit atomic memory operations by testing if the
pre-processor macro __HAVE_ATOMIC64_OPS is defined.
The atomic_swap functions first appeared in NetBSD 5.0.
NetBSD 6.1.5 April 11, 2007 NetBSD 6.1.5