Re: `initializer element is not constant' issue

[Gigi Sullivan <sullivan at sikurezza dot org>]

Aiee :)

   Hello!

On Wed, Aug 22, 2001 at 12:15:59PM +0200, Gigi Sullivan wrote:
> On Wed, Aug 22, 2001 at 04:29:48AM -0300, Alexandre Oliva wrote:
> > >    `initializer element is not constant' error from the compiler.
> > 
> > >    Is there a way to work around this, please? [1]
> > 
> > I'm afraid initializers of global variables cannot contain function
> > calls in C.
> 
>    Is it definetly just impossible?

   Ok, I found something that could be acceptable to me, a sorta
   of workaround (even, oviously, is not just what I wanted to
   do ;))

   Any comments, hints about this (3 really small C filefollows)?

   Basically I used __attribute__((constructor)) gcc extension.
   I'm aware that this is not a really portable feature (it's not
   standard) but I think that many people are using gcc right now,
   am I right? :)

-- 
Lorenzo Cavallaro	`Gigi Sullivan' <sullivan@sikurezza.org>

Until I loved, life had no beauty;
I did not know I lived until I had loved. (Theodor Korner)

#include <stdio.h>

#ifndef __TMP1_H__
#define __TMP1_H__

#define DECLARE(x) char *x
#define INIT(x) (x) = foobar(#x)

void init_foobar(void) __attribute__((constructor));
char *foobar(char *);

DECLARE(foo);
DECLARE(bar);

#endif
#include <stdio.h>
#include "tmp1.h"

void
init_foobar(void)
{

   printf("init_foobar gets executed\n");
   INIT(foo);
   INIT(bar);
  
   return;
}

char *
foobar(char *s)
{
   return s;
}
#include <stdio.h>
#include "tmp1.h"

int
main(void)
{
        
   printf("main gets executed\n");

   printf("foo: `%s'\n", foo);
   printf("bar: `%s'\n", bar);
   exit(0);
}