1typedef union 2{ 3 int __lock; 4} pthread_mutex_t; 5 6extern void abort (void); 7 8int main() 9{ 10 struct { int c; pthread_mutex_t m; } r = { .m = 0 }; 11 if (r.c != 0) 12 abort (); 13 return 0; 14} 15