suse man page for __test_and_clear_bit

__TEST_AND_CLEAR_BIT(9) 				     Basic C Library Functions					   __TEST_AND_CLEAR_BIT(9)

NAME
       __test_and_clear_bit - Clear a bit and return its old value

SYNOPSIS
       int __test_and_clear_bit(int nr, volatile unsigned long * addr);

ARGUMENTS
       nr
	   Bit to clear

       addr
	   Address to count from

DESCRIPTION
       This operation is non-atomic and can be reordered. If two examples of this operation race, one can appear to succeed but actually fail. You
       must protect multiple accesses with a lock.

COPYRIGHT
Kernel Hackers Manual 2.6.					     July 2010						   __TEST_AND_CLEAR_BIT(9)