procmail: locking problem (no timeout?)

I've posted this question to comp.mail.misc and got a reply from era
eriksson who told me to send it to this address. So here we go:

Can someone please help me with a locking problem with
procmail v3.11pre7 1997/04/28 written and created by Stephen R. van den Berg ?
It is configured to use:
Locking strategies:     dotlocking, flock()

Question:
when the folder to which procmail should deliver the mail is
locked by flock(), is it intended that no timeout occurs?
Shouldn't it timeout and return a temporary error to the caller
(sendmail)?

Unless I misunderstand the code in locking.c, it simply does:
     ret=flock(fd,LOCK_EX);
for the locking strategies configured.
In other combinations, it may produce a timeout:

     if((ret|=flock(fd,LOCK_EX|LOCK_NB))&&(errno==EAGAIN||errno==EACCES||
      errno==EWOULDBLOCK))

Is my procmail misconfigured or is this what should happen? It delays
mail delivery to a list of users indefinitely, if someone has a lock
on the folder.

Thanks,

Claus Assmann