ATOMIC_SWAP_UINT(9) | Kernel Developer's Manual | ATOMIC_SWAP_UINT(9)

# NAME

`atomic_swap_uint`, `atomic_swap_ulong`, `atomic_swap_ptr` — atomic swap operations

# SYNOPSIS

`#include <sys/atomic.h>`

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

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

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

# DESCRIPTION

The atomic_swap set of functions provide an interface for atomically performing swap operations with respect to interrupts and multiple processors in the system.

The value referenced by the pointer p is replaced by the value new.

# CONTEXT

`atomic_swap_uint`(), `atomic_swap_ulong`(), and `atomic_swap_ptr`() can all be called during autoconf, from process context, or from interrupt context.

# RETURN VALUES

These functions return the value at p as it was before the swap operation.

# SEE ALSO

atomic_cas_uint(9)

# HISTORY

The atomic_swap functions first appeared in NetBSD 5.0 and OpenBSD 5.5.

July 18, 2014 | Debian