'\"macro stdmacro
.if n .pH g2.sigblock @(#)sigblock	40.8 of 9/18/89
.\" Copyright (c) 1983 Regents of the University of California.
'\" macro stdmacro
.\" Copyright (c) 1988 Sun Microsystems, Inc. - All Rights Reserved.
.\"
.\" All rights reserved.  The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\"
.nr X
.if \nX=0 .ds x} sigblock 3 "BSD Compatibility Package" "\&"
.if \nX=1 .ds x} sigblock 3 "BSD Compatibility Package"
.if \nX=2 .ds x} sigblock 3 "" "\&"
.if \nX=3 .ds x} sigblock "" "" "\&"
.TH \*(x}
.SH NAME
\f4sigblock\f1, \f4sigmask\f1 \- block signals
.SH SYNOPSIS
\f4cc \f1[ \f2flag\f1... ] \f2file\f1 ... \f4\-lucb\f1
.P
\f4#include <signal.h>\f1
.P
.nf
\f4sigblock(mask);\f1
\f4int mask;\f1
.fi
.P
\f4#define sigmask(signum)\f1
.SH DESCRIPTION
.P
\f4sigblock\f1
adds the signals specified in
.I mask
to the set of signals currently being blocked from delivery.  Signals are
blocked if the appropriate bit in
.I mask
is a 1; the macro
\f4sigmask\f1
is provided to construct the mask for a given
.IR signum .
The previous mask is returned, and may be restored using
\f4sigsetmask\f1(3).
.P
It is not possible to block
\f4SIGKILL\f1,
\f4SIGSTOP\f1,
or
\f4SIGCONT\f1;
this restriction
is silently imposed by the system.
.SH "RETURN VALUE"
The previous set of masked signals is returned.
.SH SEE ALSO
\f4sigsetmask\fP(2),
\f4sigvec\fP(2)
.P
\f4kill\fP(2),
\f4sigaction\fP(2),
\f4signal\fP(2)
in the \f2Programmer's Reference Manual\f1.
