From:	ao950 AT FreeNet DOT Carleton DOT CA (Paul Derbyshire)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: ERROR 0004
Date:	3 Mar 1997 05:35:29 GMT
Organization:	The National Capital FreeNet
Lines:	37
Message-ID:	<5fdnv1$nc0@freenet-news.carleton.ca>
References:	<Pine DOT SUN DOT 3 DOT 91 DOT 970302125818 DOT 6609A-100000 AT is>
Reply-To:	ao950 AT FreeNet DOT Carleton DOT CA (Paul Derbyshire)
NNTP-Posting-Host:	freenet2.carleton.ca
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Eli Zaretskii (eliz AT is DOT elta DOT co DOT il) writes:
> On Thu, 27 Feb 1997, Mark T Logan wrote:
> 
>> I looked all over the DJGPP docs, but I couldn't find
>> any error number listings.  My program is crashing
>> with a page fault, and error 0004.  What is error 0004?
> 
> Please post a complete traceback printed when the program crashes.  It
> is very hard to answer your question otherwise.


0004 is general protection fault.

* Array access out of bounds
* Malloc access out of bounds
* Null pointer usage (see below)
* Pointer used before initialized
* Pointer from a malloc used before checking for NULL (but NULL from
  malloc is very rare if you have reasonable RAM and free disk, under GCC!)


below:

void main (void) {
  int a;
  a= *((int *)0);
}

This will cause a GPF.
Beware dereferencing NULL!

--
    .*.  Where feelings are concerned, answers are rarely simple [GeneDeWeese]
 -()  <  When I go to the theater, I always go straight to the "bag and mix"
    `*'  bulk candy section...because variety is the spice of life... [me]
Paul Derbyshire ao950 AT freenet DOT carleton DOT ca, http://chat.carleton.ca/~pderbysh

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