title: Linux thread id recycle strategy
body: <p>What's the recycle strategy of Linux thread ID ?</p>
  
  <p>Linux process ID will not be reused immediately unless new PID get the max limitation and being rewinded.</p>
  
  <p>When I use pthread_self() to get thread id, I got TIDs like 1028, 1034. I guess it is the inner "serial number" of threads in a process. So I guess it would be more appropriate to use a thread id recycle strategy like PID recycle strategy.
  But I am not quite sure whether it is true as to Linux pthread implementation.</p>