Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!lll-winken!uunet!portal!cup.portal.com!nicky
From: nicky@cup.portal.com (nick john pilch)
Newsgroups: comp.sys.mac.programmer
Subject: Catching Command-period
Message-ID: <16608@cup.portal.com>
Date: 3 Apr 89 00:00:26 GMT
Organization: The Portal System (TM)
Lines: 34

What would people recommend as a method to catch the Command-period
signal?  I want users to be able to cancel out of a long calculation
or something like that.  I am using MPW 3.0.  I could:

1) Use the Std C Library signal functions.  As I understand it, the safe
way to use these is to have the signal catching function set a global
flag and have the program check this flag when it wanted to.

2) Just write a function such as the one below that uses GetNextEvent and
call it when I wanted to (e.g. if (GotCancel()) ...)

Sample:

#define PERIOD_CHAR 0x2e
#define BOOLEAN int

BOOLEAN GotCancel(void)
{
	EventRecord	theEvent;
	char		theChar;
	
	GetNextEvent(keyDownMask, &theEvent);
	theChar = theEvent.message & charCodeMask;
	if ((theEvent.modifiers & cmdKey) && (theChar == PERIOD_CHAR))
		return(TRUE);
	return(FALSE);
}

Thanks for any comments.

Nick Pilch
Mountain Lake Software
nicky@cup.portal.com
AppleLink: D1036