Re: The PPP Saga Continues

[Roland McGrath]

I think that is a bug in term.  Its io_select fails with EINVAL when asked
to test for the "exception" (SELECT_URG) condition.  This is clearly
wrong--it's always valid to inquire about a condition that will never be
true.  The implementation of select in libc treats any descriptor whose
io_select RPC returns an error as having all three flavors of condition
ready, with the idea that if the program responds to this by making some
i/o call on that fd, it should see whatever the pathological error was.

That latter behavior might be a bit questionable, though I'm not sure what
else select might more usefully do instead.  But it only arises at all
because of term's intransigence.  

I'm checking in a change to term.  In the meantime, it should be reasonably
safe as a workaround to just pass NULL in place of &efds to select in ppp.