.\" Copyright (c) 1983 Regents of the University of California. .\" All rights reserved. The Berkeley software License Agreement .\" specifies the terms and conditions for redistribution. .\" .\" @(#)sigblock.2 6.3 (Berkeley) 5/14/86 .\" .TH SIGBLOCK 2 "May 14, 1986" .UC 5 .SH NAME sigblock \- block signals .SH SYNOPSIS .nf .B #include <signal.h> .B sigblock(mask); .B int mask; .B mask = sigmask(signum) .SH DESCRIPTION .I Sigblock causes the signals specified in .I mask to be added to the set of signals currently being blocked from delivery. Signals are blocked if the corresponding bit in .I mask is a 1; the macro .I sigmask is provided to construct the mask for a given .IR signum . .PP It is not possible to block SIGKILL, SIGSTOP, or SIGCONT; this restriction is silently imposed by the system. .SH "RETURN VALUE The previous set of masked signals is returned. .SH "SEE ALSO" kill(2), sigvec(2), sigsetmask(2)