GSIGNAL(3) Linux Programmer's Manual GSIGNAL(3)
gsignal, ssignal - software signal facility
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(): _SVID_SOURCE
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 ssig-
nal() 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 func-
tion 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).
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().
kill(2), signal(2), raise(3)
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