[apple/xnu.git] / bsd / man / man2 / sigsuspend.2

.\"	$NetBSD: sigsuspend.2,v 1.4 1995/02/27 12:37:46 cgd Exp $
.\"
.\" Copyright (c) 1983, 1991, 1993
.\"	The Regents of the University of California.  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.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" 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.
.\"
.\"	@(#)sigsuspend.2	8.1 (Berkeley) 6/4/93
.\"
.Dd June 4, 1993
.Dt SIGSUSPEND 2
.Os
.Sh NAME
.Nm sigsuspend
.Nd atomically release blocked signals and wait for interrupt
.Sh SYNOPSIS
.Fd #include <signal.h>
.Ft int
.Fo sigsuspend
.Fa "const sigset_t *sigmask"
.Fc
.Sh DESCRIPTION
.Fn sigsuspend
temporarily changes the blocked signal mask to the set to which
.Fa sigmask
points,
and then waits for a signal to arrive;
on return the previous set of masked signals is restored.
The signal mask set
is usually empty to indicate that all
signals are to be unblocked for the duration of the call.
.Pp
In normal usage, a signal is blocked using
.Xr sigprocmask 2
to begin a critical section, variables modified on the occurrence
of the signal are examined to determine that there is no work
to be done, and the process pauses awaiting work by using
.Fn sigsuspend
with the previous mask returned by
.Xr sigprocmask .
.Sh RETURN VALUES
The
.Fn sigsuspend
function
always terminates by being interrupted, returning -1 with
.Va errno
set to
.Dv EINTR .
.Sh SEE ALSO
.Xr sigaction 2 ,
.Xr sigprocmask 2 ,
.Xr sigsetops 3
.Sh STANDARDS
The
.Nm sigsuspend
function call
conforms to
.St -p1003.1-88 .
Commit	Line	Data
9bccf70c A	1	.\" $NetBSD: sigsuspend.2,v 1.4 1995/02/27 12:37:46 cgd Exp $
	2	.\"
	3	.\" Copyright (c) 1983, 1991, 1993
	4	.\" The Regents of the University of California. All rights reserved.
	5	.\"
	6	.\" Redistribution and use in source and binary forms, with or without
	7	.\" modification, are permitted provided that the following conditions
	8	.\" are met:
	9	.\" 1. Redistributions of source code must retain the above copyright
	10	.\" notice, this list of conditions and the following disclaimer.
	11	.\" 2. Redistributions in binary form must reproduce the above copyright
	12	.\" notice, this list of conditions and the following disclaimer in the
	13	.\" documentation and/or other materials provided with the distribution.
	14	.\" 3. All advertising materials mentioning features or use of this software
	15	.\" must display the following acknowledgement:
	16	.\" This product includes software developed by the University of
	17	.\" California, Berkeley and its contributors.
	18	.\" 4. Neither the name of the University nor the names of its contributors
	19	.\" may be used to endorse or promote products derived from this software
	20	.\" without specific prior written permission.
	21	.\"
	22	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	23	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	24	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	25	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	26	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	27	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	28	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	29	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	30	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	31	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	32	.\" SUCH DAMAGE.
	33	.\"
	34	.\" @(#)sigsuspend.2 8.1 (Berkeley) 6/4/93
	35	.\"
	36	.Dd June 4, 1993
	37	.Dt SIGSUSPEND 2
	38	.Os
	39	.Sh NAME
	40	.Nm sigsuspend
	41	.Nd atomically release blocked signals and wait for interrupt
	42	.Sh SYNOPSIS
	43	.Fd #include <signal.h>
	44	.Ft int
2d21ac55 A	45	.Fo sigsuspend
	46	.Fa "const sigset_t *sigmask"
	47	.Fc
9bccf70c	48	.Sh DESCRIPTION
39037602	49	.Fn sigsuspend
9bccf70c A	50	temporarily changes the blocked signal mask to the set to which
	51	.Fa sigmask
	52	points,
	53	and then waits for a signal to arrive;
	54	on return the previous set of masked signals is restored.
	55	The signal mask set
	56	is usually empty to indicate that all
	57	signals are to be unblocked for the duration of the call.
	58	.Pp
	59	In normal usage, a signal is blocked using
	60	.Xr sigprocmask 2
	61	to begin a critical section, variables modified on the occurrence
	62	of the signal are examined to determine that there is no work
	63	to be done, and the process pauses awaiting work by using
	64	.Fn sigsuspend
	65	with the previous mask returned by
	66	.Xr sigprocmask .
	67	.Sh RETURN VALUES
	68	The
	69	.Fn sigsuspend
	70	function
	71	always terminates by being interrupted, returning -1 with
	72	.Va errno
	73	set to
	74	.Dv EINTR .
	75	.Sh SEE ALSO
9bccf70c	76	.Xr sigaction 2 ,
2d21ac55	77	.Xr sigprocmask 2 ,
9bccf70c A	78	.Xr sigsetops 3
	79	.Sh STANDARDS
	80	The
2d21ac55	81	.Nm sigsuspend
9bccf70c A	82	function call
	83	conforms to
	84	.St -p1003.1-88 .