Article View: comp.sys.ibm.pc.programmer
Article #37Re: File buffer trashing data?
From: Jim Patterson
Date: Tue, 20 Mar 1990 14:04
Date: Tue, 20 Mar 1990 14:04
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1426 bytes
In article <1990Mar19.054020.13581@Neon.Stanford.EDU> minakami@Neon.Stanford.EDU (Michael K. Minakami) writes:
>I'm trying to debug a program and came across something unusal: fwrite()
>is changing the contents of an array. The array has memory calloc'ed
>for it at the beginning of the program, and when fwrite() is called it
>trashes everything started at array+4.
It sounds like someone has free'd your array before you're done with
it, and when you opened the file later, the buffer stdio uses was
given the area previously free'd. If you put a breakpoint in free
you might catch the offender. This might also happen without an
actual free if somehow you've corrupted the free list that malloc/free
maintain.
--
Jim Patterson Cognos Incorporated
UUCP:decvax!utzoo!dciem!nrcaer!cognos!jimp P.O. BOX 9707
PHONE:(613)738-1440 3755 Riverside Drive
Ottawa, Ont K1G 3Z4
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Path: arc1-ca.pugleaf.net!utzoo!dciem!nrcaer!sce!cognos!jimp From: jimp@cognos.UUCP (Jim Patterson) Newsgroups: comp.sys.ibm.pc.programmer,comp.sys.ibm.pc Subject: Re: File buffer trashing data? Message-ID: <8108@cognos.UUCP> Date: 20 Mar 90 14:04:40 GMT References: <1990Mar19.054020.13581@Neon.Stanford.EDU> Reply-To: jimp@cognos.UUCP (Jim Patterson) Followup-To: comp.sys.ibm.pc.programmer Organization: Cognos Inc., Ottawa, Canada Lines: 17