std::thread中獲取當前線程的系統id

std::thread不提供獲取當前線程的系統id的方法，僅可以獲取當前的線程id，但是我們可以通過建立索引表的方式來實現

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();
}

而后用其創建線程

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

然后用如下方式獲取線程id

pid_t tid = 0;
while (tid == 0)
{
  std::lock_guard<std::mutex> l(m);
  if (threads.count(t1.get_id()))
    tid = threads[t1.get_id()];
}

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