sysv_signal

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



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
       This page is part of release 5.13 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at
       https://www.kernel.org/doc/man-pages/.



                                   2021-03-22                     SYSV_SIGNAL(3)