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. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" $OpenBSD: sigblock.3,v 1.14 2007/05/31 19:19:27 jmc Exp $ 29.\" 30.Dd $Mdocdate: May 31 2007 $ 31.Dt SIGBLOCK 3 32.Os 33.Sh NAME 34.Nm sigblock 35.Nd block signals 36.Sh SYNOPSIS 37.Fd #include <signal.h> 38.Ft int 39.Fn sigblock "int mask" 40.Ft int 41.Fn sigmask "int signum" 42.Sh DESCRIPTION 43.Bf -symbolic 44This interface is made obsolete by: 45.Ef 46.Xr sigprocmask 2 . 47.Pp 48.Fn sigblock 49adds the signals specified in 50.Fa mask 51to the set of signals currently 52being blocked from delivery. 53Signals are blocked if the 54corresponding bit in 55.Fa mask 56is a 1; the macro 57.Fn sigmask 58is provided to construct the mask for a given 59.Fa signum . 60.Pp 61It is not possible to block 62.Dv SIGKILL 63or 64.Dv SIGSTOP ; 65this restriction is silently 66imposed by the system. 67.Sh RETURN VALUES 68The previous set of masked signals is returned. 69.Sh EXAMPLES 70The following example utilizing 71.Fn sigblock : 72.Bd -literal -offset indent 73int omask; 74 75omask = sigblock(sigmask(SIGINT) | sigmask(SIGHUP)); 76.Ed 77.Pp 78Becomes: 79.Bd -literal -offset indent 80sigset_t set, oset; 81 82sigemptyset(&set); 83sigaddset(&set, SIGINT); 84sigaddset(&set, SIGHUP); 85sigprocmask(SIG_BLOCK, &set, &oset); 86.Ed 87.Pp 88Another use of 89.Fn sigblock 90is to get the current set of masked signals without changing what 91is actually blocked. 92Instead of: 93.Bd -literal -offset indent 94int set; 95 96set = sigblock(0); 97.Ed 98.Pp 99Use the following: 100.Bd -literal -offset indent 101sigset_t set; 102 103sigprocmask(SIG_BLOCK, NULL, &set); 104.Ed 105.Sh SEE ALSO 106.Xr kill 2 , 107.Xr sigaction 2 , 108.Xr sigprocmask 2 , 109.Xr sigsetmask 3 , 110.Xr sigsetops 3 111.Sh HISTORY 112The 113.Fn sigblock 114function call appeared in 115.Bx 4.2 116and has been deprecated. 117