[Scsh-checkins] scsh-0.6/c/unix event.c fd-io.c socket.c

[Mike Sperber <sperber@users.sourceforge.net>]

Update of /cvsroot/scsh/scsh-0.6/c/unix
In directory usw-pr-cvs1:/tmp/cvs-serv8927/c/unix

Modified Files:
        event.c fd-io.c socket.c 
Log Message:
First stab at implementing SELECT/SELECT!:

- extend the VM interrupts to distinguish between read and write
  events
- add new ADD-PENDING-CHANNEL instruction to the VM
- add WAIT-FOR-CHANNELS procedure to the run-time system
- implement SELECT and SELECT! on top of that in newports.scm

This runs some basic tests, but in general should be considered
largely untested.

Moreover, SELECT/SELECT! never detect any exceptional conditions---the
returned vectors are always empty.  This is because the VM doesn't
really track those, and it's unclear whether it would be worth the
effort.