sigprocmask(2) [hpux man page]

sigprocmask(2)							System Calls Manual						    sigprocmask(2)

NAME

       sigprocmask() - examine and change blocked signals

SYNOPSIS

DESCRIPTION

       The function allows the calling thread to examine and/or change its signal mask.

       If the argument set is not a null pointer, it points to a set of signals to be used to change the currently blocked set.

       The argument how indicates the way in which the set is changed and consists of one of the following values:

	      The resulting set will be the union
				of the current set and the signal set pointed to by set.

	      The resulting set will be the signal set pointed to by set.

	      The resulting set will be the intersection of the
				current set and the complement of the signal set pointed to by set.

       If  the argument oset is not a null pointer, the previous mask is stored in the location pointed to by oset.  If set is a null pointer, the
       value of the argument how is not significant and the thread's signal mask is unchanged; thus the call can be used  to  inquire  about  cur-
       rently blocked signals.

       If there are any pending unblocked signals after the call to at least one of those signals will be delivered before the call to returns.

       It  is  not  possible  to  block  those	signals  which cannot  be  ignored.  This is enforced by the system without causing an error to be
       indicated.

       If any of the or signals are generated while they are blocked, the result is undefined, unless the signal was generated by a call to or

       If fails, the thread's signal mask is not changed.

RETURN VALUE

       Upon successful completion, returns 0.  Otherwise -1 is returned, is set to indicate the error,	and  the  thread's  signal  mask  will	be
       unchanged.

ERRORS

       The function will fail if:

	      The value of the
			     how argument is not equal to one of the defined values.

	      set	     or oset points to an invalid address.  The reliable detection of this error is implementation dependent.

APPLICATION USAGE

   Threads Considerations
       Each thread maintains its own blocked signal mask.  In a single-threaded process, modifies only the calling thread's blocked signal mask.

       Use of this function is unspecified in a multithreaded process.

       For more information regarding signals and threads, refer to signal(5).

   LWP (Lightweight Processes) Considerations
       modifies only the calling LWP's blocked signal mask.

AUTHOR

       was derived from the IEEE POSIX 1003.1-1988 Standard.

SEE ALSO

       sigaction(2), sigpending(2), sigsuspend(2), sigsetops(3C), pthread_sigmask(3T), signal(5).

STANDARDS CONFORMANCE

																    sigprocmask(2)

Check Out this Related Man Page

SIGPROCMASK(2)						      BSD 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
     specified 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 specified 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'').

BSD
								    May 7, 2010 							       BSD

Linux and UNIX Man Pages

sigprocmask(2) [hpux man page]

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