Direct assignment of code to function pointer: not working in gcc 4.x

[Anibal Caceres Hernando <anibal.caceres@xxxxxxxxxxxx>]

   Hi,
   The following code was working properly in gcc 3.3.3, but is not 
working if I compile it with gcc 4.1.2., it gives a Segmentation 
Violation when it's run.
What the code does do is to generate assembler opcodes and then execute 
them directly as if they were a function, using a function pointer.
Following is a simplified version of the code:

#include <stdio.h>

typedef void  (*FunctionType)();

int main() {
   char *code = new char[5];
   int codeIndex = 0;
   printf("Start!!\n");

   code[codeIndex++]=0x55; //push %ebp
   code[codeIndex++]=0x89; //mov    %esp,%ebp
   code[codeIndex++]=0xe5;    //"

   code[codeIndex++]=0xc9; //LEAVE
   code[codeIndex++]=0xc3; //RET

   FunctionType invoke=(FunctionType)&code[0];
   invoke();

   printf("Finish!!\n");
   return 0;
}

   If this is compiled with gcc 3.3.3 it executes without any problem: 
prints "Start!!", then executes invoke(), which does nothing, as you can 
see (the assembler is just a call to an empty function), and finally it 
prints "Finish!!".
   But the problem happens when I compile this using gcc 4.1.2 (and the 
same happens with 4.2.2): prints "Start!!", and it gives a Segmentation 
Violation when it starts executing invoke (I've seen using the gdb that 
the SIGSEGV happens just in the first instruction, in the "push %ebp").
   I guess something related with this should have been changed from 
gcc 3.x to gcc 4.x, and I would like to know what is it, and if there's 
a problem to have this kind of code working in gcc 4.x
   Thank you very much.
   Kind regards,

   Anibal Caceres.