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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

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       description  of  the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

                                  2007-05-04