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

NAME         top

       sysv_signal - signal handling with System V semantics

SYNOPSIS         top

       #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         top

       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         top

       The sysv_signal() function returns the previous value of the signal
       handler, or SIG_ERR on error.

ERRORS         top

       As for signal(2).

ATTRIBUTES         top

       For an explanation of the terms used in this section, see

       │Interface     Attribute     Value   │
       │sysv_signal() │ Thread safety │ MT-Safe │

CONFORMING TO         top

       This function is nonstandard.

NOTES         top

       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         top

       sigaction(2), signal(2), bsd_signal(3), signal(7)

COLOPHON         top

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       latest version of this page, can be found at

                                 2015-03-02                   SYSV_SIGNAL(3)