SIGBLOCK(3) BSD Programmer's Manual SIGBLOCK(3)NAME
sigblock - block signals
SYNOPSIS
#include <signal.h>
int
sigblock(int mask);
int
sigmask(int signum);
DESCRIPTION
This interface is made obsolete by: sigprocmask(2).
sigblock() adds the signals specified in mask to the set of signals
currently being blocked from delivery. Signals are blocked if the
corresponding bit in mask is a 1; the macro sigmask() is provided to con-
struct the mask for a given signum.
It is not possible to block SIGKILL or SIGSTOP; this restriction is
silently imposed by the system.
RETURN VALUES
The previous set of masked signals is returned.
EXAMPLES
The following example utilizing sigblock():
int omask;
omask = sigblock(sigmask(SIGINT) | sigmask(SIGHUP));
Becomes:
sigset_t set, oset;
sigemptyset(&set);
sigaddset(&set, SIGINT);
sigaddset(&set, SIGHUP);
sigprocmask(SIG_BLOCK, &set, &oset);
Another use of sigblock() is to get the current set of masked signals
without changing what is actually blocked. Instead of:
int set;
set = sigblock(0);
Use the following:
sigset_t set;
sigprocmask(SIG_BLOCK, NULL, &set);
SEE ALSOkill(2), sigaction(2), sigprocmask(2), sigsetmask(3), sigsetops(3)HISTORY
The sigblock() function call appeared in 4.2BSD and has been deprecated.
MirOS BSD #10-current March 10, 1991 1
