ATOMIC_SWAP(3) | Library Functions Manual | ATOMIC_SWAP(3)

# NAME

`atomic_swap`, `atomic_swap_32`, `atomic_swap_uint`, `atomic_swap_ulong`, `atomic_swap_ptr`, `atomic_swap_64` —
atomic swap operations

# SYNOPSIS

`#include <sys/atomic.h>`

uint32_t
`atomic_swap_32`(volatile uint32_t *ptr, uint32_t new);

unsigned int
`atomic_swap_uint`(volatile unsigned int *ptr, unsigned int new);

unsigned long
`atomic_swap_ulong`(volatile unsigned long *ptr, unsigned long new);

void *
`atomic_swap_ptr`(volatile void *ptr, void *new);

uint64_t
`atomic_swap_64`(volatile uint64_t *ptr, uint64_t new);

# DESCRIPTION

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.

# SEE ALSO

atomic_ops(3)

# HISTORY

The `atomic_swap` functions first appeared in NetBSD 5.0.

April 11, 2007 | NetBSD 9.2