SSIGNAL(3C-SVR4) RISC/os Reference Manual SSIGNAL(3C-SVR4)
NAME
ssignal, gsignal - software signals
SYNOPSIS
#include <signal.h>
int (*ssignal (int sig, int (*action) (int))) (int);
int gsignal (int sig);
DESCRIPTION
ssignal and gsignal implement a software facility similar to
signal(2). This facility is made available to users for
their own purposes.
Software signals made available to users are associated with
integers in the inclusive range 1 through 17. A call to
ssignal associates a procedure, action, with the software
signal sig; the software signal, sig, is raised by a call to
gsignal. Raising a software signal causes the action esta-
blished for that signal to be taken.
The first argument to ssignal is a number identifying the
type of signal for which an action is to be established. The
second argument defines the action; it is either the name of
a (user-defined) action function or one of the manifest con-
stants SIG_DFL (default) or SIG_IGN (ignore). ssignal
returns the action previously established for that signal
type; if no action has been established or the signal number
is illegal, ssignal returns SIG_DFL.
gsignal raises the signal identified by its argument, sig:
If an action function has been established for sig,
then that action is reset to SIG_DFL and the action
function is entered with argument sig. gsignal returns
the value returned to it by the action function.
If the action for sig is SIG_IGN, gsignal returns the
value 1 and takes no other action.
If the action for sig is SIG_DFL, gsignal returns the
value 0 and takes no other action.
If sig has an illegal value or no action was ever
specified for sig, gsignal returns the value 0 and
takes no other action.
SEE ALSO
signal(2), sigset(2), raise(3C).
Printed 11/19/92 Page 1