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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 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 glibc.
Some systems also have gsignal_r() and ssignal_r().
SEE ALSO
kill(2), signal(2), raise(3)
2021-03-22 GSIGNAL(3)