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 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).

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

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       information   about   reporting   bugs,   and   the  latest  version  of  this  page,  can  be  found  at
       http://www.kernel.org/doc/man-pages/.

                                                   2015-03-02                                     SYSV_SIGNAL(3)