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sysv_signal(3) — Linux manual page

sysv_signal(3)           Library Functions Manualsysv_signal(3)

NAME        top

       sysv_signal - signal handling with System V semantics

LIBRARY        top

       Standard C library (libc,-lc)

SYNOPSIS        top

#define _GNU_SOURCE/* See feature_test_macros(7) */#include <signal.h>typedef typeof(void (int))  *sighandler_t;sighandler_t sysv_signal(intsignum, sighandler_thandler);

DESCRIPTION        top

       Thesysv_signal() function takes the same arguments, and performs       the same task, assignal(2).       Howeversysv_signal() provides the System V unreliable signal       semantics, that is: a) the disposition of the signal is reset to       the default when the handler is invoked; b) delivery of further       instances of the signal is not blocked while the signal handler is       executing; and c) if the handler interrupts (certain) blocking       system calls, then the system call is not automatically restarted.

RETURN VALUE        top

       Thesysv_signal() function returns the previous value of the       signal handler, orSIG_ERRon error.

ERRORS        top

       As forsignal(2).

ATTRIBUTES        top

       For an explanation of the terms used in this section, seeattributes(7).       ┌──────────────────────────────────────┬───────────────┬─────────┐       │Interface│Attribute│Value│       ├──────────────────────────────────────┼───────────────┼─────────┤       │sysv_signal()                        │ Thread safety │ MT-Safe │       └──────────────────────────────────────┴───────────────┴─────────┘

VERSIONS        top

       Use ofsysv_signal() should be avoided; usesigaction(2) instead.       On older Linux systems,sysv_signal() andsignal(2) were       equivalent.  But on newer systems,signal(2) provides reliable       signal semantics; seesignal(2) for details.       The use ofsighandler_t is a GNU extension; this type is defined       only if the_GNU_SOURCEfeature test macro is defined.

STANDARDS        top

       None.

SEE ALSO        top

sigaction(2),signal(2),bsd_signal(3),signal(7)

COLOPHON        top

       This page is part of theman-pages (Linux kernel and C library       user-space interface documentation) project.  Information about       the project can be found at        ⟨https://www.kernel.org/doc/man-pages/⟩.  If you have a bug report       for this manual page, see       ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.       This page was obtained from the tarball man-pages-6.15.tar.gz       fetched from       ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on       2025-08-11.  If you discover any rendering problems in this HTML       version of the page, or you believe there is a better or more up-       to-date source for the page, or you have corrections or       improvements to the information in this COLOPHON (which isnot       part of the original manual page), send a mail to       man-pages@man7.orgLinux man-pages 6.15            2025-05-17sysv_signal(3)

Pages that refer to this page:signal(2), bsd_signal(3), signal(7)

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