The directory iterator value type objects now caches status information. Performance is much better (6 times, in one test). This optimization is present for the Windows API, and for POSIX systems which support the BSD dirent::d_type extension. Currently this is detected by the __USE_BSD macro. Please report other macros which indicate it is safe to turn on this feature. IIRC, someone indicated that Linux also supports the feature, but perhaps only on later versions. If that is the case, what is the correct macros to be tested for what values? Also, Apple OS X supplies the dirent::d_type extension, but the value isn't actually set. Any ideas on how to activate it? --Beman PS: If you want to experiment, the #if test to hack is line 65 of .../boost/filesystem/config.hpp, current CVS head.