instability in Berkeley versus AT&T releases

[Doug Gwyn <gwyn>]

> Is there a place where the differences between sysV and 4.2 are
> documented?

All such lists that I've seen, including internal documents of vendors,
have been quite incomplete.  There really seems to be little point in
such a list, unless you're a UNIX package vendor.  Only people who
specialize in this topic are likely to be able to remember most of the
differences.

The good news is, that you can develop applications under the System V
environment in such a way that they will run unmodified on any 4.2BSD
system having an appropriate compatibility package such as the BRL
emulation.  (Contact your vendor for availability of some such package.)
There are a few constraints when you use this approach, but they are
much less troublesome than trying to write code to a lowest common
denominator or with enough #ifdefs to accommodate all flavors of UNIX.