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SYSV_SIGNAL(3)             Linux Programmer's Manual            SYSV_SIGNAL(3)
NAME
       sysv_signal - signal handling with System V semantics
SYNOPSIS
       #define _GNU_SOURCE         /* See feature_test_macros(7) */
       #include <signal.h>
       typedef void (*sighandler_t)(int);
       sighandler_t sysv_signal(int signum, sighandler_t handler);
DESCRIPTION
       The  sysv_signal()  function takes the same arguments, and performs the
       same task, as signal(2).
       However sysv_signal() provides the System V  unreliable  signal  seman-
       tics, 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
       The  sysv_signal()  function  returns  the previous value of the signal
       handler, or SIG_ERR on error.
ERRORS
       As for signal(2).
ATTRIBUTES
       For  an  explanation  of  the  terms  used   in   this   section,   see
       attributes(7).
       +--------------+---------------+---------+
       |Interface     | Attribute     | Value   |
       +--------------+---------------+---------+
       |sysv_signal() | Thread safety | MT-Safe |
       +--------------+---------------+---------+
CONFORMING TO
       This function is nonstandard.
NOTES
       Use of sysv_signal() should be avoided; use sigaction(2) instead.
       On  older  Linux  systems, sysv_signal() and signal(2) were equivalent.
       But on newer systems, signal(2) provides reliable signal semantics; see
       signal(2) for details.
       The  use  of sighandler_t is a GNU extension; this type is defined only
       if the _GNU_SOURCE feature test macro is defined.
SEE ALSO
       sigaction(2), signal(2), bsd_signal(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/.
                                  2017-09-15                    SYSV_SIGNAL(3)