rt_sigpending(2) — Linux manual page


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

NAME         top

       sigpending, rt_sigpending - examine pending signals

SYNOPSIS         top

       #include <signal.h>

       int sigpending(sigset_t *set);

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

       sigpending(): _POSIX_C_SOURCE

DESCRIPTION         top

       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         top

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

ERRORS         top

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

CONFORMING TO         top

       POSIX.1-2001, POSIX.1-2008.

NOTES         top

       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         top

       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         top

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

COLOPHON         top

       This page is part of release 5.09 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

Linux                            2017-09-15                    SIGPENDING(2)

Pages that refer to this page: syscalls(2)signal(7)