Provided by:
linux-doc-2.6.15_2.6.15-23.39_all 
NAME
set_bit - Atomically set a bit in memory
SYNOPSIS
void set_bit (int nr, volatile unsigned long * addr);
ARGUMENTS
nr the bit to set
addr the address to start counting from
DESCRIPTION
This function is atomic and may not be reordered. See __set_bit if you
do not require the atomic guarantees.
NOTE
there are no guarantees that this function will not be reordered on non
x86 architectures, so if you are writting portable code, make sure not
to rely on its reordering guarantees.
Note that nr may be almost arbitrarily large; this function is not
restricted to acting on a single-word quantity.