#include <stdlib.h>
#include <stdio.h>                   /* for printf */
void tst_realloc (void) {
   void xdata *p;
   void xdata *new_p;
   p = malloc (100);
   if (p != NULL) {
      new_p = realloc (p, 200);
     if (new_p != NULL) p = new_p;
      else printf ("Reallocation failed\n");
   }
}