1  /* Copyright (C) 2000  Free Software Foundation.
       2  
       3     If the argument to va_end() has side effects, test whether side
       4     effects from that argument are honored.
       5  
       6     Written by Kaveh R. Ghazi, 10/31/2000.  */
       7  
       8  #include <stdarg.h>
       9  #include <stdio.h>
      10  #include <stdlib.h>
      11  
      12  #ifndef __GNUC__
      13  #define __attribute__(x)
      14  #endif
      15  
      16  static void __attribute__ ((__format__ (__printf__, 1, 2)))
      17  doit (const char *s, ...) 
      18  {
      19    va_list *ap_array[3], **ap_ptr = ap_array;
      20  
      21    ap_array[0] = malloc (sizeof(va_list));
      22    ap_array[1] = NULL;
      23    ap_array[2] = malloc (sizeof(va_list));
      24    
      25    va_start (*ap_array[0], s);
      26    vprintf (s, **ap_ptr);
      27    /* Increment the va_list pointer once.  */
      28    va_end (**ap_ptr++);
      29  
      30    /* Increment the va_list pointer a second time.  */
      31    ap_ptr++;
      32    
      33    va_start (*ap_array[2], s);
      34    /* If we failed to increment ap_ptr twice, then the parameter passed
      35       in here will dereference NULL and should cause a crash.  */
      36    vprintf (s, **ap_ptr);
      37    va_end (**ap_ptr);
      38  
      39    /* Just in case, If *ap_ptr is NULL abort anyway.  */
      40    if (*ap_ptr == 0)
      41      abort();
      42  }
      43  
      44  int main()
      45  {
      46    doit ("%s", "hello world\n");
      47    exit (0);
      48  }