Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!psuvax1!husc6!endor!siegel
From: siegel@endor.harvard.edu (Rich Siegel)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Dereferencing ProcPtr in LS Pascal
Message-ID: <1486@husc6.harvard.edu>
Date: 4 Feb 90 14:13:33 GMT
References: <1268@diemen.cc.utas.oz>
Sender: news@husc6.harvard.edu
Reply-To: siegel@endor.UUCP (Rich Siegel)
Organization: Symantec Language Products Group
Lines: 33

In article <1268@diemen.cc.utas.oz> brianh@tasis.UUCP (Brian Harrold) writes:
>To all Light Speed pascal gurus, I have a simple (?) question. 
>
>   I have a procedure in which one of the parameters is of type
>   ProcPtr (pointer to another procedure). Is there any way in 
>   LS Pascal to dereference the pointer to the given procedure,
>   and execute it ? 

	Dereferencing a ProcPtr is a meaningless operation, since 
"procedure" isn't a data type. However, since we all know that a ProcPtr
points to a procedure's code, it is possible to call it:

PROCEDURE CallMyProcPtr(arg1 : Type1; arg2 : Type2;...argN : TypeN; addr : ProcPtr);
INLINE $205F { movea.l (a7)+, a0 }, $4E90 { JSR (a0) };

to call it:

	CallMyProcPtr(arg1, arg2,...argN, @MyProcedure);

R.


~~~~~~~~~~~~~~~
 Rich Siegel
 Staff Software Developer
 Symantec Corporation, Language Products Group
 Internet: siegel@endor.harvard.edu
 UUCP: ..harvard!endor!siegel

"When someone who makes four hundred and fifty dollars an hour wants to
tell you something for free, it's a good idea to listen."

~~~~~~~~~~~~~~~