plan9 man page for rt_sigpending

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

NAME
       sigpending, rt_sigpending - examine pending signals

SYNOPSIS
       #include <signal.h>

       int sigpending(sigset_t *set);

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

       sigpending(): _POSIX_C_SOURCE

DESCRIPTION
       sigpending() returns the set of signals that are pending for delivery to the calling thread (i.e., the signals which have been raised while
       blocked).  The mask of pending signals is returned in set.

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

ERRORS
       EFAULT set points to memory which is not a valid part of the process address space.

CONFORMING TO
       POSIX.1-2001, POSIX.1-2008.

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

       If a signal is both blocked and has a disposition of "ignored", it is not added to the mask of pending signals when generated.

       The set of signals that is pending for a thread is the union of the set of signals that is pending for that thread and the set  of  signals
       that is pending for the process as a whole; see signal(7).

       A child created via fork(2) initially has an empty pending signal set; the pending signal set is preserved across an execve(2).

   C library/kernel differences
       The  original  Linux  system  call  was	named sigpending().  However, with the addition of real-time signals in Linux 2.2, the fixed-size,
       32-bit sigset_t argument supported by that system call was no longer fit for purpose.  Consequently, a new  system  call,  rt_sigpending(),
       was  added  to support an enlarged sigset_t type.  The new system call takes a second argument, size_t sigsetsize, which specifies the size
       in bytes of the signal set in set.  The glibc sigpending() wrapper function hides these details from us, transparently calling  rt_sigpend-
       ing() when the kernel provides it.

BUGS
       In  versions of glibc up to and including 2.2.1, there is a bug in the wrapper function for sigpending() which means that information about
       pending real-time signals is not correctly returned.

SEE ALSO
       kill(2), sigaction(2), signal(2), sigprocmask(2), sigsuspend(2), sigsetops(3), signal(7)

COLOPHON
       This page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and  the
       latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

Linux								    2017-09-15							     SIGPENDING(2)