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 4.10 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/.



				  2015-03-02			SYSV_SIGNAL(3)