ATOMIC_DEC(3) | Library Functions Manual | ATOMIC_DEC(3)

# NAME

`atomic_dec`, `atomic_dec_32`, `atomic_dec_uint`, `atomic_dec_ulong`, `atomic_dec_ptr`, `atomic_dec_64`, `atomic_dec_32_nv`, `atomic_dec_uint_nv`, `atomic_dec_ulong_nv`, `atomic_dec_ptr_nv`, `atomic_dec_64_nv` —
atomic decrement operations

# SYNOPSIS

`#include <sys/atomic.h>`

void
`atomic_dec_32`(volatile uint32_t *ptr);

void
`atomic_dec_uint`(volatile unsigned int *ptr);

void
`atomic_dec_ulong`(volatile unsigned long *ptr);

void
`atomic_dec_ptr`(volatile void *ptr);

void
`atomic_dec_64`(volatile uint64_t *ptr);

uint32_t
`atomic_dec_32_nv`(volatile uint32_t *ptr);

unsigned int
`atomic_dec_uint_nv`(volatile unsigned int *ptr);

unsigned long
`atomic_dec_ulong_nv`(volatile unsigned long *ptr);

void *
`atomic_dec_ptr_nv`(volatile void *ptr);

uint64_t
`atomic_dec_64_nv`(volatile uint64_t *ptr);

# DESCRIPTION

The `atomic_dec` family of functions decrement (by one) the variable referenced by ptr in an atomic fashion.

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

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_dec` functions first appeared in NetBSD 5.0.

April 11, 2007 | NetBSD 9.3