#define DECLARE_PER_THREAD(type, name) extern DEFINE_PER_THREAD(type, name)
#define per_thread(name, thread) __per_thread_##name[thread].v
#define DECLARE_PER_THREAD(type, name) extern DEFINE_PER_THREAD(type, name)
#define per_thread(name, thread) __per_thread_##name[thread].v