__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
       bool __test_and_set_bit(long nr, volatile unsigned long * addr);

ARGUMENTS
       nr
           Bit to set

       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 4.8.                 January 2017                     __TEST_AND_SET_BIT(9)