NAME

atomic_dec_int, atomic_dec_int_nv, atomic_dec_long, atomic_dec_long_nv — atomic decrement operations

SYNOPSIS

#include <>

void
atomic_dec_int(volatile unsigned int *p);

unsigned int
atomic_dec_int_nv(volatile unsigned int *p);

void
atomic_dec_long(volatile unsigned long *p );

unsigned long
atomic_dec_long_nv(volatile unsigned long *p);

DESCRIPTION

The atomic_dec set of functions provide an interface for atomically performing decrement and decrement-and-fetch operations with respect to interrupts and multiple processors in the system.

The value referenced by the pointer p is decremented by 1.

CONTEXT

atomic_dec_int(), atomic_dec_int_nv(), atomic_dec_long(), and atomic_dec_long_nv() can all be called during autoconf, from process context, or from interrupt context.

RETURN VALUES

atomic_dec_int and atomic_dec_long perform the decrement without returning any knowledge of the value at p.

atomic_dec_int_nv and atomic_dec_long_nv return the value at p after the decrement was performed.

SEE ALSO

atomic_add_int(9), atomic_inc_int(9)

HISTORY

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