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From: dor@beach.cis.ufl.edu (Douglas R. Oosting)
Newsgroups: comp.lang.pascal
Subject: Re: Trapping (fatal) runtime errors in TP 5.0
Keywords: Exit procedures
Message-ID: <20892@uflorida.cis.ufl.EDU>
Date: 15 Sep 89 13:31:31 GMT
References: <486@oetl1.oetl.UUCP>
Sender: news@uflorida.cis.ufl.EDU
Reply-To: dor@beach.cis.ufl.edu (Douglas R. Oosting)
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Organization: UF CIS Department
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In article <486@oetl1.oetl.UUCP> randy@oetl.UUCP (Randy O'Meara) writes:
>
>	Does anyone know how to trap the fatal runtime errors in
>	Turbo 5.0?  I'm interested in recovering from real math
>	overflow.  Thanks.
>

Its fairly simple...you declare a procedure for error-handling somewhere
in your code.  Put a {$F+} and a {$F-} compiler directive around it
[force far call ON for the procedure, turn it back OFF afterwards]

Now, in your initialization code, make these two declarations...

ExitSave := ExitProc    [ExitProc is declared for you, ExitSave is a POINTER]
ExitProc := @MyErrorProc (or whatever)

The last statement of your error handler (refered to as MyErrorProc above)
must be   ExitProc := ExitSave

(Exiting a program is a chain procedure; this process inserts your trapper
*before* the Turbo one.  It will be called every time you exit, so you will
want to check the error condition to make sure you *need* to do anything.

Doug Oosting  
>-- 
>Randy O'Meara		randy@oetl.Scf.Lockheed.Com
>(408) 425-6249		...{pyramid,leadsv,lstc}!oetl!randy


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