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content-class: urn:content-classes:message
Subject: RE: gcc 3.3.1 problem
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Date: Mon, 29 Sep 2003 10:05:39 +0200
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From: =?iso-8859-1?Q?J=F6rg_Schaible?= <Joerg DOT Schaible AT Elsag-Solutions DOT com>
To: <cygwin AT cygwin DOT com>
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Hi Gerry,

you return a pointer to an object on the stack, that is no longer valid after leaving your function. So any value printed in main is undefined and you can get any result.

Regards,
Jörg

Gerry Reno wrote on Monday, September 29, 2003 9:34 AM:

>   I'm having a problem with gcc 3.3.1.  Here is a sample
> program that demos the problem:
> 
> // test.c
> #include <stdio.h>
> #include <windows.h>
> 
> typedef struct abc {
>   HANDLE h1;
>   HANDLE h2;
> } XYZ;
> 
> XYZ * somefunc () {
>   XYZ xyz;
>   XYZ *ptr = &xyz;
> 
>   ptr->h1 = (HANDLE) 99;
>   ptr->h2 = (HANDLE) 88;
> 
> printf("somefunc: ptr->h1 = %d\n",ptr->h1);
> printf("somefunc: ptr->h2 = %d\n",ptr->h2);
> 
>   return (ptr);
> }
> 
> int main(void) {
>   XYZ *ptr2;
> 
>   ptr2 = somefunc ();
> printf("main: ptr2->h1 = %d\n",ptr2->h1);
> printf("main: ptr2->h2 = %d\n",ptr2->h2);
> 
> }
> ------------------------------
> 
> -- results --
> somefunc: ptr->h1 = 99
> somefunc: ptr->h2 = 88
> main: ptr2->h1 = 99
> main: ptr2->h2 = 99
> 
> 
>   And sometimes it will give me really large values for main: ptr2-h2
> like 4043574. 
> 
> ----------------------
> Env:
> Cygwin 1.5.5
> gcc 3.3.1
> 
> 
> 
> 
> =====
> Gerry Reno
> mailto: grenoml at@ yahoo dot. com
> (if mail bounces please retry later - spam rapidly fills up mailbox)
> 
> __________________________________
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