user stack layout Help

[gztime]

Hi, everybody,

I have a little program as the following:

/*******************
this is to test satck-layout
moscowliuyong(at)hotmail.com
********************/

#include <string.h>
#include <stdio.h>

int main()
{

char str[4];
char s[4];
int x=1;
strcpy(s,"12345");
strcpy(str,s);
printf("x=%d, \t\tstr=%s, \t\ts=%s\n",x, str,s);
printf("&x=%p,\tstr->%p,\ts->%p\n",&x,str,s);
}


I compiled and got different results in different system:
on Solaris sytem, the result is not "correct", but understandable.
on BSD system, the result is correct,but I'm confused bythe real stack layout.

The results of the program is as the following:

-bash-3.00$ cat solaris.output
x=889192449, str=12345, s=5
&x=ffbffce8, str->ffbffce0, s->ffbffce4

-bash-3.00$ cat bsd.output
x=1, str=12345, s=12345
&x=0x7fffffffebcc, str->0x7fffffffebe0, s->0x7fffffffebd0

My question is: where the string s is stored??

[gerard4143]

try compiling your program with -S and look at the assembled code it will show you where the char s[4] is stored. This said, char s[4] should be stored on the stack...Hope this helps

gcc -S test.c

[gerard4143]

Also try compiling the program with -g and check it in the gdb(gnu debugger)

gcc -g -o test test.c

here's a link to a gdb tutorial, just in case you never used gdb

Peter's gdb Tutorial: Table Of Contents