#include <unistd.h>

#define STRINGIFY(x) #x

#define TOSTRING(x) STRINGIFY(x)

#define CURRENT_LOCATION __FILE__ ":" TOSTRING(__LINE__)

#define err()                         \

{                                     \

  _fail("at " CURRENT_LOCATION " ");  \

}

#define mb() asm volatile ("" : : : "memory")

extern void pass(void);

extern void _fail(char *reason);