120 lines
3.2 KiB
Groff
120 lines
3.2 KiB
Groff
.\" Copyright (c) 1983, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" from: @(#)sigblock.2 8.1 (Berkeley) 6/2/93
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.\" $NetBSD: sigblock.3,v 1.17 2003/08/07 16:42:40 agc Exp $
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.\"
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.Dd August 10, 2002
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.Dt SIGBLOCK 3
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.Os
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.Sh NAME
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.Nm sigblock
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.Nd block signals
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In signal.h
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.Ft int
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.Fn sigblock "int mask"
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.Ft int
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.Fn sigmask signum
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.Sh DESCRIPTION
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.Bf -symbolic
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This interface is made obsolete by:
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.Xr sigprocmask 2 .
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.Ef
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.Pp
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.Fn sigblock
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adds the signals specified in
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.Fa mask
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to the set of signals currently
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being blocked from delivery.
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Signals are blocked if the
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corresponding bit in
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.Fa mask
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is a 1; the macro
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.Fn sigmask
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is provided to construct the mask for a given
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.Fa signum .
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.Pp
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It is not possible to block
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.Dv SIGKILL
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or
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.Dv SIGSTOP ;
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this restriction is silently
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imposed by the system.
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.Sh RETURN VALUES
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The previous set of masked signals is returned.
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.Sh EXAMPLES
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The following example using
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.Fn sigblock :
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.Bd -literal -offset indent
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int omask;
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omask = sigblock(sigmask(SIGINT) | sigmask(SIGHUP));
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.Ed
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.Pp
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Becomes:
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.Bd -literal -offset indent
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sigset_t set, oset;
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sigemptyset(&set);
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sigaddset(&set, SIGINT);
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sigaddset(&set, SIGHUP);
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sigprocmask(SIG_BLOCK, &set, &oset);
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.Ed
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.Pp
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Another use of
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.Fn sigblock
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is to get the current set of masked signals without changing what
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is actually blocked.
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Instead of:
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.Bd -literal -offset indent
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int set;
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set = sigblock(0);
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.Ed
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.Pp
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Use the following:
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.Bd -literal -offset indent
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sigset_t set;
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sigprocmask(SIG_BLOCK, NULL, &set);
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.Ed
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.Sh SEE ALSO
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.Xr kill 2 ,
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.Xr sigaction 2 ,
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.Xr sigprocmask 2 ,
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.Xr sigsetmask 3 ,
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.Xr sigsetops 3
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.Sh HISTORY
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The
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.Fn sigblock
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function call appeared in
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.Bx 4.2
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and has been deprecated.
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