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Command Section
SIGSETMASK(2)             FreeBSD System Calls Manual            SIGSETMASK(2)

NAME
     sigsetmask, sigblock - manipulate current signal mask

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <signal.h>

     int
     sigsetmask(int mask);

     int
     sigblock(int mask);

     int
     sigmask(int signum);

DESCRIPTION
     This interface is made obsolete by: sigprocmask(2).

     The sigsetmask() function sets the current signal mask to the specified
     mask.  Signals are blocked from delivery if the corresponding bit in mask
     is a 1.  The sigblock() function adds the signals in the specified mask
     to the current signal mask, rather than overwriting it as sigsetmask()
     does.  The macro sigmask() is provided to construct the mask for a given
     signum.

     The system quietly disallows SIGKILL or SIGSTOP to be blocked.

RETURN VALUES
     The sigblock() and sigsetmask() functions return the previous set of
     masked signals.

SEE ALSO
     kill(2), sigaction(2), sigprocmask(2), sigsuspend(2), sigvec(2),
     sigsetops(3)

HISTORY
     The sigsetmask() and sigblock() functions first appeared in 4.2BSD and
     have been deprecated.

FreeBSD 11.1-RELEASE-p4          June 2, 1993          FreeBSD 11.1-RELEASE-p4
Command Section