1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" from: @(#)sigblock.2 8.1 (Berkeley) 6/2/93 33.\" $NetBSD: sigblock.3,v 1.14 2002/08/10 09:07:15 wiz Exp $ 34.\" 35.Dd August 10, 2002 36.Dt SIGBLOCK 3 37.Os 38.Sh NAME 39.Nm sigblock 40.Nd block signals 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.Fd #include \*[Lt]signal.h\*[Gt] 45.Ft int 46.Fn sigblock "int mask" 47.Ft int 48.Fn sigmask signum 49.Sh DESCRIPTION 50.Bf -symbolic 51This interface is made obsolete by: 52.Xr sigprocmask 2 . 53.Ef 54.Pp 55.Fn sigblock 56adds the signals specified in 57.Fa mask 58to the set of signals currently 59being blocked from delivery. 60Signals are blocked if the 61corresponding bit in 62.Fa mask 63is a 1; the macro 64.Fn sigmask 65is provided to construct the mask for a given 66.Fa signum . 67.Pp 68It is not possible to block 69.Dv SIGKILL 70or 71.Dv SIGSTOP ; 72this restriction is silently 73imposed by the system. 74.Sh RETURN VALUES 75The previous set of masked signals is returned. 76.Sh EXAMPLES 77The following example utilizing 78.Fn sigblock : 79.Bd -literal -offset indent 80int omask; 81 82omask = sigblock(sigmask(SIGINT) | sigmask(SIGHUP)); 83.Ed 84.Pp 85Becomes: 86.Bd -literal -offset indent 87sigset_t set, oset; 88 89sigemptyset(&set); 90sigaddset(&set, SIGINT); 91sigaddset(&set, SIGHUP); 92sigprocmask(SIG_BLOCK, &set, &oset); 93.Ed 94.Pp 95Another use of 96.Fn sigblock 97is to get the current set of masked signals without changing what 98is actually blocked. 99Instead of: 100.Bd -literal -offset indent 101int set; 102 103set = sigblock(0); 104.Ed 105.Pp 106Use the following: 107.Bd -literal -offset indent 108sigset_t set; 109 110sigprocmask(SIG_BLOCK, NULL, &set); 111.Ed 112.Sh SEE ALSO 113.Xr kill 2 , 114.Xr sigaction 2 , 115.Xr sigprocmask 2 , 116.Xr sigsetmask 3 , 117.Xr sigsetops 3 118.Sh HISTORY 119The 120.Fn sigblock 121function call appeared in 122.Bx 4.2 123and has been deprecated. 124