sigprocmask(2) [opensolaris man page]

sigprocmask(2)							   System Calls 						    sigprocmask(2)

NAME

       sigprocmask - change or examine caller's signal mask

SYNOPSIS

       #include <signal.h>

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

DESCRIPTION

       The sigprocmask() function is used to examine and/or change the caller's signal mask. If the value is  SIG_BLOCK, the set pointed to by the
       set argument is added to the current signal mask. If the value is  SIG_UNBLOCK, the set pointed by the  set argument is	removed  from  the
       current	signal	mask. If the value is  SIG_SETMASK, the current signal mask is replaced by the set pointed to by the  set argument. If the
       oset argument is not  NULL, the previous mask is stored in the space pointed to by oset. If the value of the  set argument  is	NULL,  the
       value  how is not significant and the caller's signal mask is unchanged; thus, the call can be used to inquire about currently blocked sig-
       nals. If the set or oset argument points to an invalid address, the behavior is undefined and errno may be set to EFAULT.

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

       It  is  not possible to block signals that cannot be caught or ignored (see sigaction(2)). It is also not possible to block or unblock SIG-
       CANCEL, as SIGCANCEL is reserved for the implementation of POSIX thread cancellation (see  pthread_cancel(3C)  and  cancellation(5)).  This
       restriction is silently enforced by the standard C library.

       If sigprocmask() fails, the caller's signal mask is not changed.

RETURN VALUES

       Upon successful completion, 0 is returned. Otherwise, -1 is returned and errno is set to indicate the error.

ERRORS

       The sigprocmask() function will fail if:

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

       The sigprocmask() function may fail if:

       EFAULT	 The set or oset argument points to an illegal address.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |Async-Signal-Safe 	   |
       +-----------------------------+-----------------------------+

SEE ALSO

       sigaction(2), pthread_cancel(3C), pthread_sigmask(3C), signal(3C), signal.h(3HEAD), sigsetops(3C), attributes(5), cancellation(5)

NOTES

       The call to sigprocmask() affects only the calling thread's signal mask. It is identical to a call to pthread_sigmask(3C).

       Signals that are generated synchronously should not be masked. If such a signal is blocked and delivered, the receiving process is killed.

SunOS 5.11							    23 Mar 2005 						    sigprocmask(2)

Check Out this Related Man Page

SIGPROCMASK(2)						     Linux Programmer's Manual						    SIGPROCMASK(2)

NAME

       sigprocmask - examine and change blocked signals

SYNOPSIS

       #include <signal.h>

       int sigprocmask(int how, const sigset_t *set, sigset_t *oldset);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       sigprocmask(): _POSIX_C_SOURCE >= 1 || _XOPEN_SOURCE || _POSIX_SOURCE

DESCRIPTION

       sigprocmask()  is  used to fetch and/or change the signal mask of the calling thread.  The signal mask is the set of signals whose delivery
       is currently blocked for the caller (see also signal(7) for more details).

       The behavior of the call is dependent on the value of how, as follows.

       SIG_BLOCK
	      The set of blocked signals is the union of the current set and the set argument.

       SIG_UNBLOCK
	      The signals in set are removed from the current set of blocked signals.  It is permissible to attempt to unblock a signal  which	is
	      not blocked.

       SIG_SETMASK
	      The set of blocked signals is set to the argument set.

       If oldset is non-NULL, the previous value of the signal mask is stored in oldset.

       If set is NULL, then the signal mask is unchanged (i.e., how is ignored), but the current value of the signal mask is nevertheless returned
       in oldset (if it is not NULL).

       The use of sigprocmask() is unspecified in a multithreaded process; see pthread_sigmask(3).

RETURN VALUE

       sigprocmask() returns 0 on success and -1 on error.  In the event of an error, errno is set to indicate the cause.

ERRORS

       EFAULT the set or oldset argument points outside the process's allocated address space.

       EINVAL The value specified in how was invalid.

CONFORMING TO

       POSIX.1-2001.

NOTES

       It is not possible to block SIGKILL or SIGSTOP.	Attempts to do so are silently ignored.

       Each of the threads in a process has its own signal mask.

       A child created via fork(2) inherits a copy of its parent's signal mask; the signal mask is preserved across execve(2).

       If SIGBUS, SIGFPE, SIGILL, or SIGSEGV are generated while they are blocked, the result is undefined, unless the	signal	was  generated	by
       kill(2), sigqueue(3), or raise(3).

       See sigsetops(3) for details on manipulating signal sets.

SEE ALSO

       kill(2), pause(2), sigaction(2), signal(2), sigpending(2), sigsuspend(2), pthread_sigmask(3), sigqueue(3), sigsetops(3), signal(7)

COLOPHON

       This  page is part of release 3.53 of the Linux man-pages project.  A description of the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

Linux								    2013-04-19							    SIGPROCMASK(2)

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sigprocmask(2) [opensolaris man page]

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