Tribblix: manual page: atomic

ATOMIC_CAS(9F) Kernel Functions for Drivers ATOMIC_CAS(9F)

NAME

atomic_cas, atomic_cas_8, atomic_cas_uchar, atomic_cas_16,
atomic_cas_ushort, atomic_cas_32, atomic_cas_uint, atomic_cas_ulong,
atomic_cas_64, atomic_cas_ptr - atomic compare and swap operations

SYNOPSIS

#include <sys/atomic.h>

uint8_t atomic_cas_8(volatile uint8_t *target, uint8_t cmp, uint8_t
newval);

uchar_t atomic_cas_uchar(volatile uchar_t *target, uchar_t cmp, uchar_t
newval);

uint16_t atomic_cas_16(volatile uint16_t *target, uint16_t cmp, uint16_t
newval);

ushort_t atomic_cas_ushort(volatile ushort_t *target, ushort_t cmp,
ushort_t newval);

uint32_t atomic_cas_32(volatile uint32_t *target, uint32_t cmp, uint32_t
newval);

uint_t atomic_cas_uint(volatile uint_t *target, uint_t cmp, uint_t newval);

ulong_t atomic_cas_ulong(volatile ulong_t *target, ulong_t cmp, ulong_t
newval);

uint64_t atomic_cas_64(volatile uint64_t *target, uint64_t cmp, uint64_t
newval);

void *atomic_cas_ptr(volatile void *target, void *cmp, void *newval);

DESCRIPTION

These functions enable a compare and swap operation to occur
atomically. The value stored in target is compared with cmp. If these
values are equal, the value stored in target is replaced with newval.
The old value stored in target is returned by the function whether or
not the replacement occurred.

RETURN VALUES

These functions return the old of *target.

ERRORS

No errors are defined.

CONTEXT

These functions can be called from user, interrupt, or kernel
context.

ATTRIBUTES