Is my created thread still running ???

I have written a muti threaded application in which one of my threads(the main one) wants to know whether a thread previously created is  still running or has exited but i cannot join this thread as it has to take inputs from the front end (ncurses based text grahicall frontend)   i can only check peridically if the thread is still alive and also would like to retrive the return status code of the (if) exited thread.
is there any function through which i can know that a particular  is still active or exited.

pl reply as soonn as possible
-Rohan