How to write a current directory finder?

[Felix Lee]

Doing a "trace" shows that getwd() does not chdir().

Here is speculation on Sun's getwd() after trying to implement my own
and watching a "trace".

* It caches its result.  Repeated calls to getwd() just make two
stat() calls.  Trying to time the performance of getwd() by putting it
in a loop is meaningless.  This is the big win.

* It uses /tmp/.getwd to figure out where it is when it crosses a
mount point.  This is a minor gain.  In my version of getwd(), I
stat'ed around to find the mount point; commenting out the stat()
calls saved about .005s system time (on a Sun4 running SunOS4.0).

Any other differences in algorithm (using fstat() instead of stat(),
using chdir(), etc.) have little effect on performance.
--
Felix Lee	flee at shire.cs.psu.edu	*!psuvax1!shire!flee