Re: debugging threads vs processes

["Nic Ferrier" <nferrier at tapsellferrier dot co dot uk>]

>>> Per Bothner <per@bothner.com> 13-Jul-01 1:20:29 AM >>>

   Does someone on this list understand Linux threads 
   enough to explain what is going on and/or suggest 
   useful debugging tools?

I understand them a bit, enough I think to explain what's going on. I
apologise if this is not technical enough for you.

Linux threads are light weight processes. One creates them with the
clone() system call which does  almost exactly the same as fork.

In effect they are created exactly the same as processes.


    One problem is how I can get a list of running 
   processes vs threads?

I'm not sure that's possible except through your app.


   The pid field is the result of getpid(), the prev field 
   is the value saved by the last request in a static 
   variable.  ps -H claims that 16694 and 16697 are 
   siblings, not parent/child.  But then how can 16697 
   remember a static value set by 16694?  Unless they 
   are two threads in the same process, in which case 
   getpid is returning the thread id, rather than a process id.

Got me there. Are they both talking back to the data stored in the
parent?


Nic