> well i thought i'd coded it before.
> 
> look at pipe.c:

Thanks, Boyd, for the guidelines and also to Nemo for suggesting a
similar tack in previous private mail.

I have no idea whether this is adequate, but it matches some
superficial expectations, at least.

I'm including my efforts here because I'm going away for the weekend
and somebody may have the opportunity in the meantime to look at the
code and use it, but more specially to inspect it and hopefully make
suggestions on how to improve it (other than in code layout, I have a
great deal of trouble omitting spaces as seems to be the norm in Plan
9 sources, sorry about that).

I'll be grateful for all and any feedback, please be alerted that the
code is designed for use in the APE environment, modelled on the
NetBSD wait(2) man page I mentioned earlier.  It is intended to
replace

	/sys/src/ape/lib/ap/plan9/wait.c

in its entirety, but I have not checked this to any degree.  The
module compiles and runs with

	$ pcc -D_PLAN9_SOURCE -D_POSIX_SOURCE -I/sys/src/ape/lib/ap/plan9 -c pidwait.c
	$ 8l -o pidwait pidwait.8
	$ pidwait

from my home directory.

++L