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SIGPROCMASK(2)		  FreeBSD System Calls Manual		SIGPROCMASK(2)

NAME
     sigprocmask -- manipulate current signal mask

LIBRARY
     Standard C	Library	(libc, -lc)

SYNOPSIS
     #include <signal.h>

     int
     sigprocmask(int how, const	sigset_t * restrict set,
	 sigset_t * restrict oset);

DESCRIPTION
     The sigprocmask() system call examines and/or changes the current signal
     mask (those signals that are blocked from delivery).  Signals are blocked
     if	they are members of the	current	signal mask set.

     If	set is not null, the action of sigprocmask() depends on	the value of
     the how argument.	The signal mask	is changed as a	function of the	speci-
     fied set and the current mask.  The function is specified by how using
     one of the	following values from <signal.h>:

     SIG_BLOCK	  The new mask is the union of the current mask	and the	speci-
		  fied set.

     SIG_UNBLOCK  The new mask is the intersection of the current mask and the
		  complement of	the specified set.

     SIG_SETMASK  The current mask is replaced by the specified	set.

     If	oset is	not null, it is	set to the previous value of the signal	mask.
     When set is null, the value of how	is insignificant and the mask remains
     unset providing a way to examine the signal mask without modification.

     The system	quietly	disallows SIGKILL or SIGSTOP to	be blocked.

     In	threaded applications, pthread_sigmask(3) must be used instead of
     sigprocmask().

RETURN VALUES
     The sigprocmask() function	returns	the value 0 if successful; otherwise
     the value -1 is returned and the global variable errno is set to indicate
     the error.

ERRORS
     The sigprocmask() system call will	fail and the signal mask will be
     unchanged if one of the following occurs:

     [EINVAL]		The how	argument has a value other than	those listed
			here.

SEE ALSO
     kill(2), sigaction(2), sigpending(2), sigsuspend(2), fpsetmask(3),
     pthread_sigmask(3), sigsetops(3)

STANDARDS
     The sigprocmask() system call is expected to conform to ISO/IEC
     9945-1:1990 (``POSIX.1'').

FreeBSD	9.3			  May 7, 2010			   FreeBSD 9.3

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | SEE ALSO | STANDARDS

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