Ok, after a long search I did find where it was written. After installation of ocamelwin one has to read the readme win file . There one says that there are no threads for Cygwin Ocamel but there are threads for Mingw Ocamel and of course for MVSC6.0 Ocamel . I hope this information is still correct allthough I don't understand the why: what is the difference between Mingw and Cygwin? Thx Scott ----- Original Message ----- From: Scott J, To: CAML-LIST Sent: Sunday, September 15, 2002 4:52 PM Subject: [Caml-list] Thread library Hi, I have looked in the reference manual. But there is some thing that surprises me: The thread library is not available for Unix an Cygwin Windows but is available for Windows MVSC6.0 and MINGW Windows. Is this true or have I misread something? Thx Scott