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GSIGNAL(3)                 Linux Programmer's Manual                GSIGNAL(3)
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  gsig-
       nal(),  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)