1 #include <stdlib.h> 2 debug(void)3int __attribute__ ((noinline)) debug (void) { return 1; } 4 int errors; 5 6 struct s { int elt; int (*compare) (int); }; 7 8 static int compare(const void * x,const void * y)9compare (const void *x, const void *y) 10 { 11 const struct s *s1 = x, *s2 = y; 12 int (*compare1) (int); 13 int elt2; 14 15 compare1 = s1->compare; 16 elt2 = s2->elt; 17 if (elt2 != 0 && debug () && compare1 (s1->elt) != 0) 18 errors++; 19 return compare1 (elt2); 20 } 21 bad_compare(int x)22int bad_compare (int x) { return -x; } 23 struct s array[2] = { { 1, bad_compare }, { -1, bad_compare } }; 24 25 int main(void)26main (void) 27 { 28 qsort (array, 2, sizeof (struct s), compare); 29 return errors == 0; 30 } 31