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Subject: [Boost-build] Multiple calls to "using boost" with the same version
From: Anthony Foglia (AFoglia_at_[hidden])
Date: 2009-06-11 21:29:52

        In our project we have a sysdefs.jam file at the top of the directory
structure that sets up the rules for most of the libraries. I just
replaced the 200+ lines we had for boost libraries with aliases to the
boost libraries as defined in the boost.jam file that comes with boost.

        While working up to this change, I set up a user-config.jam of my own
to set up boost. Very simple, configures both the system version of
boost 1.35, and a version of 1.38 I downloaded and compiled in my home

        When I changed our repository code, since we haven't been using
site-config.jam, I put a "using boost" rule in our sysdefs.jam file
(located in the same directory as our Jamroot). Bjam complained that
"Boost 1.35 already configured."

        I patched boost.jam to test for duplicate initializations, and if the
new settings are the same as the old, do nothing. (And print a warning
if .debug-configuration is set.)

        Is there a better way? Should/Can I test before calling "using boost"
in the sysdefs to see if it's been defined earlier (e.g.
user-config.jam)? Should/Can I catch the error instead?

Anthony Foglia
Princeton Consultants
(609) 987-8787 x233

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