Hi Anthony ! The latest change to Boost.Thread: URL: http://svn.boost.org/trac/boost/changeset/40348 introduced "feature.feature thrd-api" as "symmetric" feature, adding "thrd-api-pthread" to the build paths on linux. I'd like to have it asymmetric, so build paths will be as short as possible. The problem with the "symmetric" property is that you can't use "feature.set-default" to change the default value so the path element will disappear. Please find "thread.diff" with propose patch attached. Also thread.txt with output without patch and thread2.txt will patched Jamfile.v2. The other thing I noticed is the usage of "os.name" to distinguish between nt/unix/cygwin. I think this should use "target-os" in order to enable cross-compilation, but I don't know how to code this. Therefore cross-post to Boost.Build list in order to get some pointer on how to change if [ os.name ] = NT to if target-os = windows or something similar. Yours, Jürgen -- * Dipl.-Math. Jürgen Hunold ! Ingenieurgesellschaft für * voice: ++49 511 262926 57 ! Verkehrs- und Eisenbahnwesen mbH * fax : ++49 511 262926 99 ! Lister Straße 15 * juergen.hunold@ivembh.de ! www.ivembh.de * * Geschäftsführer: ! Sitz des Unternehmens: Hannover * Prof. Dr.-Ing. Thomas Siefer ! Amtsgericht Hannover, HRB 56965 * PD Dr.-Ing. Alfons Radtke !