gsignal(3) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | ATTRIBUTES | CONFORMING TO | SEE ALSO | COLOPHON

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

NAME         top

       gsignal, ssignal - software signal facility

SYNOPSIS         top

       #include <signal.h>

       typedef void (*sighandler_t)(int);

       int gsignal(int signum);

       sighandler_t ssignal(int signum, sighandler_t action);

   Feature Test Macro Requirements for glibc (see
   feature_test_macros(7)):

       gsignal(), ssignal():
           Since glibc 2.19:
               _DEFAULT_SOURCE
           Glibc 2.19 and earlier:
               _SVID_SOURCE

DESCRIPTION         top

       Don't use these functions under Linux.  Due to a historical
       mistake, under Linux these functions are aliases for raise(3) and
       signal(2), respectively.

       Elsewhere, on System V-like systems, these functions implement
       software signaling, entirely independent of the classical
       signal(2) and kill(2) functions.  The function ssignal() defines
       the action to take when the software signal with number signum is
       raised using the function gsignal(), and returns the previous
       such action or SIG_DFL.  The function gsignal() does the
       following: if no action (or the action SIG_DFL) was specified for
       signum, then it does nothing and returns 0.  If the action
       SIG_IGN was specified for signum, then it does nothing and
       returns 1.  Otherwise, it resets the action to SIG_DFL and calls
       the action function with argument signum, and returns the value
       returned by that function.  The range of possible values signum
       varies (often 1–15 or 1–17).

ATTRIBUTES         top

       For an explanation of the terms used in this section, see
       attributes(7).

       ┌──────────────────────────────┬───────────────┬─────────────────┐
       │Interface                     Attribute     Value           │
       ├──────────────────────────────┼───────────────┼─────────────────┤
       │gsignal()                     │ Thread safety │ MT-Safe         │
       ├──────────────────────────────┼───────────────┼─────────────────┤
       │ssignal()                     │ Thread safety │ MT-Safe sigintr │
       └──────────────────────────────┴───────────────┴─────────────────┘

CONFORMING TO         top

       These functions are available under AIX, DG/UX, HP-UX, SCO,
       Solaris, Tru64.  They are called obsolete under most of these
       systems, and are broken under glibc.  Some systems also have
       gsignal_r() and ssignal_r().

SEE ALSO         top

       kill(2), signal(2), raise(3)

COLOPHON         top

       This page is part of release 5.12 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                     GSIGNAL(3)