asynchronous I/O in system V

[Doug Gwyn <gwyn>]

> I am looking for a way to do asynchronous I/O under System V in
> a similar way to the BSD select() call.

Nope.  The closest you can come is to use O_NDELAY reads,
the minimum-character-count & -time kludges in termio,
and sometimes FIFOs.

Select() is supposed to appear at some future date along
with stream I/O.  This is about the ONLY "foreign" syscall
I find useful in applications developed under our UNIX
System V emulation on 4.2BSD.  Part of the reason it is
taking a while to show up in the AT&T product is that it
necessitates modifying all the device drivers.