The thread_dev branch in CVS contains a number of changes to the thread_specific_ptr / tss implementation that I would like to move to the main branch. I plan to look at it more carefully before I do so, but will anyone interested please take a look at the implementation on the thread_dev branch to see if has any problems (or if there are known problems that it doesn't fix)? It contains changes to fix a number of issues with the current implementation, including, among others: 1) thread_specific_ptr::reset() doesn't check error: http://lists.boost.org/MailArchives/boost/msg55713.php. 2) Double deletes: http://lists.boost.org/MailArchives/boost/msg50266.php, http://lists.boost.org/MailArchives/boost/msg50543.php, http://lists.boost.org/MailArchives/boost/msg30433.php, http://lists.boost.org/MailArchives/boost-users/msg05531.php. 3) Not enough tss keys/slots: http://lists.boost.org/MailArchives/boost/msg55376.php, http://lists.boost.org/MailArchives/boost/msg55712.php. 4) Ability to register custom cleanup functions. For reference, see: tss.hpp, http://cvs.sourceforge.net/viewcvs.py/*checkout*/boost/boost/boost/thread/tss.hpp?content-type=text%2Fplain&rev=1.6.2.5 tss.cpp, http://cvs.sourceforge.net/viewcvs.py/*checkout*/boost/boost/libs/thread/src/tss.cpp?content-type=text%2Fplain&rev=1.6.2.4 threadmon.cpp, http://cvs.sourceforge.net/viewcvs.py/*checkout*/boost/boost/libs/thread/src/threadmon.cpp?content-type=text%2Fplain&rev=1.7.2.2 Mike