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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_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

   This page is part of release 4.09 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/.



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