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From: Baiss E. Magnusson <BMagnusson@PrecisionImages.com>
Newsgroups: comp.lang.beta
Subject: Globals & External C Lib
Date: 29 Apr 1995 21:12:50 GMT
Organization: PDI
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X-XXDate: Sat, 29 Apr 1995 22:11:47 GMT

I'm not clear on how to set up the Beta code to make a call to an
external 'C' library routine that wants the address of a variable passed
( i.e. call by reference rather than call by value). Just a simple
example of a 'C" routine that uses the address of an <unsigned short>
would suffice. As in the call to <GetIMAXXType> below:

Also, I would like to group all globals variables in a single class, but
one of the errors I get is:

myGlobals: @GlobarVars
***** Only pattern-declarations may appear in a fragment of category
'attributes'

******************
I heve in fragment <Init.bet>
******************
myGlobals: @GlobarVars;	 

GlobarVars:
(#
	boardType :			@ExternalRecord;
	actualVidParms :	@VidParamStruct;	
	displayBaseAddr : 	@integer;		(* physical address of display memory *)
.......
#);
......
ConnectIMAXX:external (# do callC #);
GetIMAXXType:external (# bType: @shortInt; enter bType.ptr do callC; exit
bType #);
......
InitGrabber:
(#
	do
		ConnectIMAXX;
		myGlobals.boardType -> GetIMAXXType->myGlobals.boardType;  (* ??????? *)
......
#)
******************
Then in the main program:
******************
do
	globvar[] -> initToolbox;
	SetUpMenus;
	(windowId,0,-1) -> getNewWindow -> myWindow -> setPort;
	InitGrabber;
.....