[SOLVED] gcc compile error

[PastorTaz]

I'm working on a practical exam on smashing a stack. I'm running Feisty on a Dell 820. I have Feisty in both VMWare and native boot.

The code I'm using is C++. Here is the code used...



void function (char *str)

{
char buffer [100];
strcpy(buffer, str); //The strcpy function does not check for bounds
}

int main ()
{
char string[512];
int i;

for (i=0; i<512; i++) //loop 512 times
{
string[i] = 'A';
}
function(string);
exit(0);
}


When I use gcc I get this error

root@vm-ubuntu:/lpt/ceptlab# gcc -o overflow3 overflow.c
overflow.c: In function ‘function’:
overflow.c:5: warning: incompatible implicit declaration of built-in function ‘strcpy’
overflow.c: In function ‘main’:
overflow.c:18: warning: incompatible implicit declaration of built-in function ‘exit’
root@vm-ubuntu:/lpt/ceptlab#

When I use gcc-3.3 it compiles just fine.

Can anyone tell me why?
Thanks,

[Wybiral]

Did you:


#include <stdlib.h>
#include <string.h>

?

If so, you may need to install "build-essential"



sudo apt-get install build-essential

[PastorTaz]

No I did not use those includes.

Should I install build-essential anyway?

[xtacocorex]

Yes, build-essential contains the compilers and the libraries needed to compile.

[Wybiral]

No I did not use those includes.

Should I install build-essential anyway?

Well, "strcpy" is from "string.h" and "exit" is from "stdlib.h" so you will need to include them. If you include them and still get errors, then you might not have the headers which is why I say to get "build-essential".

[PastorTaz]

Thanks Wybiral! It worked like a charm.