messagemode named pipes investigation: blocking-reads block writers indefinitely

[Luke Kenneth Casson Leighton]

fascinatingly strange observation came out of writing the latest test
(threadwrites) to do namedpipe interoperability testing.

main process: blocking-read on namedpipe.
5 threads: write to same named pipe

the writes NEVER return (this is with xp).

so that WOULD indicate that there IS a per-pipe mutex (and that there
are bugs in nt!)

l.