SYSV_SIGNAL(3)                                      Linux Programmer's Manual                                     SYSV_SIGNAL(3)



NAME
       sysv_signal - signal handling with System V semantics

SYNOPSIS
       #define _GNU_SOURCE
       #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 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
       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), feature_test_macros(7), signal(7)

COLOPHON
       This  page  is  part of release 3.25 of the Linux man-pages project.  A description of the project, and information about
       reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.



                                                           2007-05-04                                             SYSV_SIGNAL(3)