.TH "test_and_clear_bit" 9 "test_and_clear_bit" "25 May 1998" "Kernel Hacker's Manual" LINUX
.SH NAME
test_and_clear_bit \-  Clear a bit and return its old value
.SH SYNOPSIS
.B "int" test_and_clear_bit
.BI "(int " nr ","
.BI "volatile void *" addr ");"
.SH ARGUMENTS
.IP "nr" 12
 Bit to clear
.IP "addr" 12
 Address to count from
.SH "DESCRIPTION"
This operation is atomic and cannot be reordered.  
It also implies a memory barrier.