|SIGBLOCK(3)||Library Functions Manual||SIGBLOCK(3)|
— block signals
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
is provided to construct the mask for a given
It is not possible to block
SIGSTOP; this restriction is silently imposed by the
The previous set of masked signals is returned.
The following example utilizing
int omask; omask = sigblock(sigmask(SIGINT) | sigmask(SIGHUP));
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.
int set; set = sigblock(0);
Use the following:
sigset_t set; sigprocmask(SIG_BLOCK, NULL, &set);
sigblock() system call first appeared in
4.2BSD. In 4.3BSD-Reno, it
was reimplemented as a wrapper around
sigprocmask(2). The old system call
was kept for compatibility until OpenBSD 4.9.
|August 1, 2017||OpenBSD-current|