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Article #3025Re: TC 2.0 odd behaviour, me or it ?
From: Steve Resnick
Date: Tue, 13 Nov 1990 18:09
Date: Tue, 13 Nov 1990 18:09
27 lines
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1866 bytes
In article <16962@hydra.gatech.EDU> np4@prism.gatech.EDU (POMPONIO,NICHOLAS A) writes: [Stuff Deleted] > >As I understand it, the TC runtime system checks location 0:0 at exit time to >see if it was modified. If so, it prints the warning message. Thus, even >though the message occurs at the end of the program, the actual Null pointer >assignment could occur any anywhere in the program. This is not entirely true. BTW - THIS IS IN THE FAQ LIST. I make mention that this isn't true since playing with things at address 0:0 could be real painful. The NULL pointer assignement comes from the C runtime (on TC, in C0?.OBJ) in memory models which use 16bit pointers (relative to DS). When the program writes data to a NULL pointer in these models, the C runtime warns of this at the termination of the program. If you are using 32bit pointers, writing data to NULL will overwrite the interrupt vector table. This is an important consideration if you are doing modeling in small model and then moving to a larger memory model when doing your "production" code. Hope this helps.... Steve -- ---------------------------------------------------------------------------- steve.resnick@f105.n143.z1.FIDONET.ORG - or - apple!camphq!105!steve.resnick Flames, grammar errors, spelling errrors >/dev/nul The Asylum OS/2 BBS - (408)263-8017 IFNA 1:143/105.0
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Path: arc1-ca.pugleaf.net!utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!apple!vsi1!octopus!stever From: stever@Octopus.COM (Steve Resnick ) Newsgroups: comp.os.msdos.programmer Subject: Re: TC 2.0 odd behaviour, me or it ? Message-ID: <1990Nov13.180900.17455@Octopus.COM> Date: 13 Nov 90 18:09:00 GMT References: <7129@castle.ed.ac.uk> <16962@hydra.gatech.EDU> Reply-To: stever@octopus.UUCP (Steve Resnick ) Organization: Octopus Enterprises, Cupertino CA Lines: 27