# Manual browser: atomic_swap(3)

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 7.0 |