Date: Wed, 22 Jan 1997 07:25:59 -0500 (EST)
From: "Mike A. Harris" <mharris AT sympatico DOT ca>
Reply-To: "Mike A. Harris" <mharris AT sympatico DOT ca>
To: Adam Kunen <kkunen AT facstaff DOT wisc DOT edu>
cc: djgpp AT delorie DOT com
Subject: Re: Bug report: Structs
In-Reply-To: <199701220247.UAA37718@audumla.students.wisc.edu>
Message-ID: <Pine.LNX.3.95.970122072309.141N-100000@capslock.com>
Organization: Your mom.
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII

On Tue, 21 Jan 1997, Adam Kunen wrote:

>         I think this is the right address for bug reports on DOS port of GNU 
> C... But anyway, I was using GNU C and found that when you have a structure 
> bigger than 64k it tends to crash.  Although I havn't spent time to pinpoint 
> exactly what is causing the problem, I beleive that it crashes when you make 
> a function call with a large structure as an argument.  I assume that doing 
> this is okay because gcc doesn't report any warnings or errors, so I've come 
> to the conclusion: It's a bug!
>         I hope this helps,
>                         Adam Kunen,
>                         kkunen AT facstaff DOT wisc DOT edu
> 
> 
> 
> 
> PS: I was told to give an example code file to illustrate the problem:
> 
> struct FooType {
>         char blah[1024][128];
> };
> 
> void foobar(struct FooType ptr){
>         return;
> }
> 
> int main(void){
>         struct FooType eek;
>         foobar(eek);
>         return 0;
> }

You are passing a 128k struct to the function foobar().  This is
placed on the stack!!!!!  You should never pass a struct to a
function.  Pass the address instead.

ie:
void foobar(struct FooType *ptr)
{return;}

Then in main put:
foobar(&eek);

Good luck.


Mike A. Harris  -  Computer Consultant   http://www3.sympatico.ca/mharris
My dynamic address:      http://www3.sympatico.ca/mharris/ip-address.html
mailto:mharris AT sympatico DOT ca        mailto:mharris AT blackwidow DOT saultc DOT on DOT ca

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