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_sigpending() 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

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