CedarConsole.mesa
Copyright Ó 1986, 1990, 1991 by Xerox Corporation. All rights reserved.
Brent Welch September 25, 1990 11:48 am PDT
CedarConsole: CEDAR DEFINITIONS = BEGIN
Introduction
CedarConsole is used to divert UNIX system error messages to a standard place provided by the Feedback interface. Because it really grabs the console (/dev/console) its use has to be carefully coordinated with (typically) RawViewers. The diversion has to cease when RawViewers wants to return control to the underlying commander. Otherwise, if the Commander had been using the console for input and output, the the act of diverting the console to the Feedback interface effectively steals the I/O streams from the Commander. Strange but true. Therefore there are two calls into the CedarConsole interface, Start and Stop.
Start:
PROC []
RETURNS [];
Start UNIX error message diversion to Feedback.
Stop:
PROC []
RETURNS [];
Stop UNIX error message diversion to Feedback.
There is also a CommandProc registered under "Console [on|off]"
END.