From:	av568 AT rgfn DOT epcc DOT edu (Beautiful Savior Lutheran Church)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: SIGSEGV when doing file operations
Date:	31 Mar 1997 23:32:05 GMT
Organization:	The Rio Grande Free-Net, El Paso Community College, El Paso, TX
Message-ID:	<5hphhl$f5g@news.epcc.edu>
References:	<5hp58q$cn9 AT nexp DOT crl DOT com>
NNTP-Posting-Host:	rgfn.epcc.edu
Lines:	27
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Kyle R. Hofmann (rhofmann AT crl DOT com) wrote:
> I'm trying to use fread to read in parts of a file, and it segfaults 
> every time.  What I do is:

> Call my function OpenFile, which:
> -Opens the file.
> -Reads 4 bytes using fread() and checks if they are what they should be.
> -Reads 4 more bytes using fread() and stores them.
> -Returns.
> Call my function ReadData, which promptly crashes when doing anything 
> file related.

> I've done various things at the point where it crashes, and so far fread(), 
> fseek(), ftell(), and even fclose() all die at that point.  This is 
> _very_ annoying, especially since another program I tried compiling that 
> does file I/O works fine.  Symifying the tracebacks gives me _fread+22, 
> _fseek+20, _ftell+9, and _fclose+28 as the places where it dies.  I tried 
> moving the fopen out of OpenFile and into main(), but that causes it to 
> crash at ___dj_movedata+33, called from _fread+129.

It's hard to tell what the problem is. On the surface, it looks like 
you're trying to use a local pointer that has expired, but no one can be 
sure without seeing the source.

--
Beautiful Savior Evangelical Lutheran Church - av568 AT rgfn DOT epcc DOT edu
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