See the README.threads in the main perl 5.004_xx development distribution (x >= 50) for details of how to build and use this. If all else fails, read on. If your version of patch can't create a file from scratch, then you'll need to create an empty thread.h manually first. Perl itself will need to be built with -DUSE_THREADS yet. If you're using MIT pthreads or another threads package that needs pthread_init() to be called, then add -DNEED_PTHREAD_INIT. If you're using a threads library that only follows one of the old POSIX drafts, then you'll probably need to add -DOLD_PTHREADS_API. I haven't tested -DOLD_PTHREADS_API properly yet and I think you may still have to tweak a couple of the mutex calls to follow the old API. This extension is copyright Malcolm Beattie 1995-1997 and is freely distributable under your choice of the GNU Public License or the Artistic License (see the main perl distribution). Malcolm Beattie mbeattie@sable.ox.ac.uk