1) I checked out modular Boost as per https://svn.boost.org/trac/boost/wiki/TryModBoost 2) Changed libs/multiprecision to the develop branch also as per https://svn.boost.org/trac/boost/wiki/TryModBoost 3) Added some pending changes from the old SVN Trunk that I didn't commit before the changeover. 4) Ran the tests and everything failed, even though it was passing on SVN :-(
The issue was that the headers under boost/ were now *copies* of the last release and no longer pointers to the new "develop" code. Interestingly some of the hard links were updated when I ran bjam, but apparently not all :-(
Running bjam -a fixes the issue, but it's a very easy trap for the unwary.... John.
And another thing.... Ran "bjam -a headers" from the root directory to force the headers to be rebuilt, and the tests now build and pass OK... except that's a mistake because I see that old test results that depend on those headers were *not* rebuilt. So you need to bjam -a from the libs/mylib/test directory as well whenever you change branches :-( John.