header cacheing, etc.

From: David Abrahams (david.abrahams_at_[hidden])
Date: 2002-05-24 07:25:34

I was getting tired of waiting for builds to start, especially when I was
building over my slow wireless LAN connection, so I grabbed Matt
Armstrong's improvements on Craig McPheeters' header cacheing patches (and
a few other things) for jam_src. I made some mistakes with the checkin, so
they're sitting on the end of the RC_1_28_0 branch, though I think that tag
didn't get moved. The right way to get them is by checking out the
"header-cache" tag in jam_src:

cvs update -rheader-cache tools/build/jam_src

In my experience (cursory tests) the patch slows things down slightly
unless you set the HCACHEFILE variable to point at the cache dependency
file you want it to use, in which case after the first build, you get an
enormous speedup.

I'm prepared to merge the changes, but thought I should give people a
chance to look at them first.

-Dave

+---------------------------------------------------------------+
David Abrahams
C++ Booster (http://www.boost.org) O__ ==
Pythonista (http://www.python.org) c/ /'_ ==
resume: http://users.rcn.com/abrahams/resume.html (*) \(*) ==
email: david.abrahams_at_[hidden]
+---------------------------------------------------------------+