1.\" Copyright (c) 1983, 1991 The Regents of the University of California. 2.\" 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.\" $OpenBSD: sigblock.3,v 1.11 2001/03/11 05:02:28 aaron Exp $ 33.\" 34.Dd March 10, 1991 35.Dt SIGBLOCK 3 36.Os 37.Sh NAME 38.Nm sigblock 39.Nd block signals 40.Sh SYNOPSIS 41.Fd #include <signal.h> 42.Ft int 43.Fn sigblock "int mask" 44.Ft int 45.Fn sigmask "int signum" 46.Sh DESCRIPTION 47.Bf -symbolic 48This interface is made obsolete by: 49.Ef 50.Xr sigprocmask 2 . 51.Pp 52.Fn sigblock 53adds the signals specified in 54.Fa mask 55to the set of signals currently 56being blocked from delivery. 57Signals are blocked if the 58corresponding bit in 59.Fa mask 60is a 1; the macro 61.Fn sigmask 62is provided to construct the mask for a given 63.Fa signum . 64.Pp 65It is not possible to block 66.Dv SIGKILL 67or 68.Dv SIGSTOP ; 69this restriction is silently 70imposed by the system. 71.Sh EXAMPLES 72The following example utilizing 73.Fn sigblock : 74.Bd -literal -offset indent 75int omask; 76 77omask = sigblock(sigmask(SIGINT) | sigmask(SIGHUP)); 78.Ed 79.Pp 80Becomes: 81.Bd -literal -offset indent 82sigset_t set, oset; 83 84sigemptyset(&set); 85sigaddset(&set, SIGINT); 86sigaddset(&set, SIGHUP); 87sigprocmask(SIG_BLOCK, &set, &oset); 88.Ed 89.Pp 90Another use of 91.Fn sigblock 92is to get the current set of masked signals without changing what 93is actually blocked. 94Instead of: 95.Bd -literal -offset indent 96int set; 97 98set = sigblock(0); 99.Ed 100.Pp 101Use the following: 102.Bd -literal -offset indent 103sigset_t set; 104 105sigprocmask(SIG_BLOCK, NULL, &set); 106.Ed 107.Sh RETURN VALUES 108The previous set of masked signals is returned. 109.Sh SEE ALSO 110.Xr kill 2 , 111.Xr sigaction 2 , 112.Xr sigprocmask 2 , 113.Xr sigsetmask 3 , 114.Xr sigsetops 3 115.Sh HISTORY 116The 117.Fn sigblock 118function call appeared in 119.Bx 4.2 120and has been deprecated. 121