Multithreaded behavior of new Solaris 8 /dev/poll

Question

When one thread is blocked in the ioctl for the /dev/poll device
(to retrieve the fd's with events), a write from a different thread
to add to the set appears to block indefinitely.
I figured this ability (to add to the set from a different thread
with no mutexing) was a great feature, but it looks like the
write call blocks indefinitely. Before I invest in the unfortunate
workaround, I wondered if anyone had dealt with this before.
Thanks.

Answer 1

I have not yet extracted a simple program, but the basics are:
Thread one:
fd1 = open()
fd2 = open()
fdp = open("/dev/poll"..)
ioctl(fdp, DP_POLL, ...)
Thread two (later):
write(fdp, {struct with fd1, and POLLIN});
... much successful operation of the first thread receiving
events from the ioctl, and properly "dispatching" them
write(fdp, {struct fd1, and POLLREMOVE);
It is this second write that hangs indefinitely.
The only way I get it to NOT hang is by giving the
ioctl(DP_POLL) in the first thread a timeout.
When the ioctl returns due to timeout, the second thread that was hung in
"write", finally returns.
(my email is [email protected])
Thanks for any ideas or help.