NAME

       gsignal, ssignal - software signal facility

SYNOPSIS

       #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

       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

       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

       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 Linux libc and glibc.
       Some systems also have gsignal_r() and ssignal_r().

SEE ALSO

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

COLOPHON

       This page is part of release 4.15 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/.

                                            2017-09-15                                 GSIGNAL(3)