std::thread中获取当前线程的系统id

std::thread不提供获取当前线程的系统id的方法，仅可以获取当前的线程id，但是我们可以通过建立索引表的方式来实现

 std::mutex m;
 std::map<std::thread::id, pid_t> threads;
 void add_tid_mapping()
 {
   std::lock_guard<std::mutex> l(m);
   threads[std::this_thread::get_id()] = syscall(SYS_gettid);
 }
 void wrap(void (*f)())
 {
   add_tid_mapping();
   f();
 }

而后用其创建线程

 std::thread t1(&wrap, &SayHello);

然后用如下方式获取线程id

 pid_t tid = ;
 while (tid == )
 {
   std::lock_guard<std::mutex> l(m);
   if (threads.count(t1.get_id()))
     tid = threads[t1.get_id()];
 }

转自：https://stackoverflow.com/questions/15708983/how-can-you-get-the-linux-thread-id-of-a-stdthread