NAME
atomic_dec_int,
atomic_dec_int_nv,
atomic_dec_long,
atomic_dec_long_nv —
atomic decrement operations
SYNOPSIS
#include
<sys/atomic.h>
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
HISTORY
The atomic_add functions first appeared in NetBSD 5.0 and OpenBSD 5.5.