sysv_signal


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).

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  only  defined
       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 3.35 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://man7.org/linux/man-pages/.



                                  2007-05-04                    SYSV_SIGNAL(3)
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