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

atomic_swap_uint, atomic_swap_ulong, atomic_swap_ptr
atomic swap operations

#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);

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.

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

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


The atomic_swap functions first appeared in NetBSD 5.0 and OpenBSD 5.5.
July 18, 2014 OpenBSD-current