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


NAME


atomic_add, atomic_add_8, atomic_add_char, atomic_add_16,
atomic_add_short, atomic_add_32, atomic_add_int, atomic_add_long,
atomic_add_64, atomic_add_ptr, atomic_add_8_nv, atomic_add_char_nv,
atomic_add_16_nv, atomic_add_short_nv, atomic_add_32_nv,
atomic_add_int_nv, atomic_add_long_nv, atomic_add_64_nv,
atomic_add_ptr_nv - atomic add operations

SYNOPSIS


#include <sys/atomic.h>

void atomic_add_8(volatile uint8_t *target, int8_t delta);


void atomic_add_char(volatile uchar_t *target, signed char delta);


void atomic_add_16(volatile uint16_t *target, int16_t delta);


void atomic_add_short(volatile ushort_t *target, short delta);


void atomic_add_32(volatile uint32_t *target, int32_t delta);


void atomic_add_int(volatile uint_t *target, int delta);


void atomic_add_long(volatile ulong_t *target, long delta);


void atomic_add_64(volatile uint64_t *target, int64_t delta);


void atomic_add_ptr(volatile void *target, ssize_t delta);


uint8_t atomic_add_8_nv(volatile uint8_t *target, int8_t delta);


uchar_t atomic_add_char_nv(volatile uchar_t *target, signed char delta);


uint16_t atomic_add_16_nv(volatile uint16_t *target, int16_t delta);


ushort_t atomic_add_short_nv(volatile ushort_t *target, shortdelta);


uint32_t atomic_add_32_nv(volatile uint32_t *target, int32_t delta);


uint_t atomic_add_int_nv(volatile uint_t *target, int delta);


ulong_t atomic_add_long_nv(volatile ulong_t *target, long delta);


uint64_t atomic_add_64_nv(volatile uint64_t *target, int64_t delta);


void *atomic_add_ptr_nv(volatile void *target, ssize_t delta);


DESCRIPTION


These functions enable the addition of delta to the value stored in
target to occur in an atomic manner.

RETURN VALUES


The *_nv() variants of these functions return the new value of target.

ERRORS


No errors are defined.

CONTEXT


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

ATTRIBUTES


See attributes(5) for descriptions of the following attributes:


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Committed |
+--------------------+-----------------+

SEE ALSO


atomic_and(9F), atomic_bits(9F), atomic_cas(9F), atomic_dec(9F),
atomic_inc(9F), atomic_or(9F), atomic_swap(9F), membar_ops(9F),
attributes(5), atomic_ops(3C)

NOTES


The *_nv() variants are substantially more expensive on some platforms
than the versions that do not return values. Do not use them unless you
need to know the new value atomically (for example, when decrementing a
reference count and checking whether it went to zero).


January 16, 2006 ATOMIC_ADD(9F)