On Mon, 29 Sep 2003, Gerry Reno wrote:
> 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
Tsk, tsk, tsk, Gerry, you should really know better than to return a
pointer to an automatic variable (a struct, in this case). That's one of
the things K&R explicitly warns against. You're lucky it worked at all in
the previous versions of gcc. If you want to return a pointer to
something from a function, either make it global, or static, or allocate
it dynamically.
Igor
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