How can you get the Linux thread Id of a std::thread()

Question

I was playing with std::thread and I was wondering how is it possible to get the thread id of a new std::thread(), I am not talking about std::t

Answer 1

Some pthread implementations, e.g. Android 21+, provide

pid_t pthread_gettid_np(pthread_t);

The implementation may use the internal structure of struct pthread_t to retrieve the native thread id, same as the one returned by gettid() or syscall(SYS_gettid) when called in the context of that thread.