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.\"
.\" Copyright 2013 Samy Al Bahra.
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"
.Dd April 7, 2013
.Dt ck_pr_fence_memory 3
.Sh NAME
.Nm ck_pr_fence_memory
.Nd enforce partial ordering of all memory operations
.Sh LIBRARY
Concurrency Kit (libck, \-lck)
.Sh SYNOPSIS
.In ck_pr.h
.Ft void
.Fn ck_pr_fence_memory
.Ft void
.Fn ck_pr_fence_strict_memory
.Sh DESCRIPTION
The
.Fn ck_pr_fence_memory 3
function enforces the ordering of any memory operations
with respect to the invocation of the function. This function
always serves as an implicit compiler barrier.
Achitectures implementing CK_MD_TSO do not emit
a barrier, but compiler barrier semantics remain.
Architectures implementing CK_MD_PSO and CK_MD_RMO always emit
an instructions which provides the specified ordering
guarantees. To force the unconditional emission of a memory
fence, use
.Fn ck_pr_fence_strict_memory .
.Sh EXAMPLE
.Bd -literal -offset indent
#include <ck_pr.h>
static int a = 0;
static int b;
static int c;
static int d;
void
function(void)
{
int snapshot_a;
ck_pr_store_int(&b, 1);
snapshot_a = ck_pr_load_int(&a);
/*
* Make sure previous memory operations are
* ordered with respect to memory operations
* following the ck_pr_fence_memory.
*/
ck_pr_fence_memory();
ck_pr_store_int(&d, 3);
ck_pr_store_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 3 ,
.Xr ck_pr_fence_atomic_store 3 ,
.Xr ck_pr_fence_atomic_load 3 ,
.Xr ck_pr_fence_load 3 ,
.Xr ck_pr_fence_load_depends 3 ,
.Xr ck_pr_fence_store 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/
|
