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ATOMIC_DEC_INT(9)        BSD Kernel Developer's Manual       ATOMIC_DEC_INT(9)

NAME
     atomic_dec_int, atomic_dec_int_nv, atomic_dec_long, atomic_dec_long_nv --
     atomic decrement operations

SYNOPSIS
     #include <&lt;sys/atomic.h>&gt;

     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 per-
     forming 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 con-
     text, or from interrupt context.

RETURN VALUES
     atomic_dec_int and atomic_dec_long perform the decrement without return-
     ing 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.

BSD                            February 13, 2014                           BSD