Why do I see one more thread than the number I created in my `ps` listing?

Question

When I create a thread (pthread_create()) from my main process, I see three (3) threads in the ps listing, why is this? That is, I see the process

Answer 1

It is likely the "thread manager" thread. See answer D.5 at this link.

You won't see the extra process listed on most modern Linux systems if they are using NPTL. But I searched and it sounds like BusyBox uses ulibc which I think only added NPTL support recently. So I don't know for sure, but my guess is you are using LinuxThreads and seeing the manager thread as the extra thread.