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.Dd May 16, 2013
.Dt CK_PR_FENCE_ATOMIC 3
.Sh NAME
.Nm ck_pr_fence_atomic
.Nd enforce partial ordering of atomic read-modify-write operations
.Sh LIBRARY
Concurrency Kit (libck, \-lck)
.Sh SYNOPSIS
.In ck_pr.h
.Ft void
.Fn ck_pr_fence_atomic void
.Ft void
.Fn ck_pr_fence_strict_atomic void
.Sh DESCRIPTION
The
.Fn ck_pr_fence_atomic
function enforces the ordering of any
atomic read-modify-write operations relative to
the invocation of the function. This function
always serve as an implicit compiler barrier. On
architectures implementing CK_MD_TSO, this operation
only serves as a compiler barrier and no fences
are emitted. On architectures implementing
CK_MD_PSO and CK_MD_RMO, a store fence is
emitted. To force the unconditional emission of
a fence, use
.Fn ck_pr_fence_strict_atomic .
.Sh EXAMPLE
.Bd -literal -offset indent

#include <ck_pr.h>

static int a = 0;
static int b = 0;
static int c = 0;

void
function(void)
{

	ck_pr_fas_int(&a, 1);

	/*
	 * Guarantee that the update to a is completed
	 * with respect to the updates of b and c.
	 */
	ck_pr_fence_atomic();
	ck_pr_fas_int(&b, 2);
	ck_pr_fas_int(&c, 2);

	return;
}
.Ed
.Sh RETURN VALUES
This function has no return value.
.Sh SEE ALSO
.Xr ck_pr_stall 3 ,
.Xr ck_pr_fence_atomic_store 3 ,
.Xr ck_pr_fence_atomic_load 3 ,
.Xr ck_pr_fence_store 3 ,
.Xr ck_pr_fence_load 3 ,
.Xr ck_pr_fence_load_atomic 3 ,
.Xr ck_pr_fence_load_store 3 ,
.Xr ck_pr_fence_load_depends 3 ,
.Xr ck_pr_fence_memory 3 ,
.Xr ck_pr_barrier 3 ,
.Xr ck_pr_fas 3 ,
.Xr ck_pr_load 3 ,
.Xr ck_pr_store 3 ,
.Xr ck_pr_faa 3 ,
.Xr ck_pr_inc 3 ,
.Xr ck_pr_dec 3 ,
.Xr ck_pr_neg 3 ,
.Xr ck_pr_not 3 ,
.Xr ck_pr_add 3 ,
.Xr ck_pr_sub 3 ,
.Xr ck_pr_and 3 ,
.Xr ck_pr_or 3 ,
.Xr ck_pr_xor 3 ,
.Xr ck_pr_cas 3 ,
.Xr ck_pr_btc 3 ,
.Xr ck_pr_bts 3 ,
.Xr ck_pr_btr 3
.Pp
Additional information available at http://concurrencykit.org/
