clear_bit(9) [centos man page]

CLEAR_BIT(9)						     Basic C Library Functions						      CLEAR_BIT(9)

NAME

       clear_bit - Clears a bit in memory

SYNOPSIS

       void clear_bit(int nr, volatile unsigned long * addr);

ARGUMENTS

       nr
	   Bit to clear

       addr
	   Address to start counting from

DESCRIPTION

       clear_bit is atomic and may not be reordered. However, it does not contain a memory barrier, so if it is used for locking purposes, you
       should call smp_mb__before_clear_bit and/or smp_mb__after_clear_bit in order to ensure changes are visible on other processors.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014							      CLEAR_BIT(9)

ATOMIC_DEC(3)						   BSD 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.

BSD
								  April 11, 2007							       BSD