If you are interested in the actual '*quickest* way to get a list of all folders in a directory' on Windows then you'll need either an XS extension or external C program *.

Why? Because the pure Perl code typically used to do this task of opendir/readdir/-d will make unnecesary extra system calls. At the Win32 API level Perl's readdir is done by FindNextFile() which returns a WIN32_FIND_DATA structure that contains whether the returned file is a directory. Unfortunately this info is not kept so you must then stat() it to test if it's a directory. This extra work can amount to a significant overhead.

And also remember to:  ${^WIN32_SLOPPY_STAT} = 1; to avoid more extraneous system calls (unless you are actually interested in the link count of stat'd files!)

* I use qfind to efficiently find all the files in a directory. Modifying it to do what you want is left as an exercise :-) You can find it at http://backpan.perl.org/authors/id/A/AD/ADAVIES/qfind.c-1.06

alex.