SSIGNAL(S) XENIX System V SSIGNAL(S)
Name
ssignal, gsignal - Implements software signals.
Syntax
#include <signal.h>
int (*ssignal (sig, action))( )
int sig, (*action)( );
int gsignal (sig)
int sig;
Description
ssignal and gsignal implement a software facility similar to
signal(S). This facility is used by the standard C library
to enable the user to indicate the disposition of error
conditions, and is also made available to the user for his
own purposes.
Software signals made available to users are associated with
integers in the inclusive range 1 through 15. An action for
a software signal is established by a call to ssignal, and a
software signal is raised by a call to gsignal. Raising a
software signal causes the action established 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
constants 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.
Page 1 (printed 8/7/87)
SSIGNAL(S) XENIX System V SSIGNAL(S)
Notes
There are some additional signals with numbers outside the
range 1 through 15 that are used by the standard C library
to indicate error conditions. Thus, some signal numbers
outside the range 1 through 15 are legal, although their use
may interfere with the operation of the standard C library.
Page 2 (printed 8/7/87)