Davide Libenzi wrote:

>Why would you need to use threads with a multiplex-like interface like
>/dev/epoll ?
>
Because in some applications processing an event can cause the thread to 
block, potentially for a long time.  Multiple threads are needed to 
isolate that block to the context associated with the event.

>	while (read() == EGAIN)
>		wait(POLLIN);
>  
>
Assuming registration of interest is inside wait(), this has a race.  If 
the file becomes readable between the time that read() returns and the 
time that wait() can register interest, the connection will hang.