suse man page for test_and_set_bit

TEST_AND_SET_BIT(9)					     Basic C Library Functions					       TEST_AND_SET_BIT(9)

NAME
       test_and_set_bit - Set a bit and return its old value

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

ARGUMENTS
       nr
	   Bit to set

       addr
	   Address to count from

DESCRIPTION
       This operation is atomic and cannot be reordered. It also implies a memory barrier.

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