I believe thread.h in your case is specific to SunOS which supports (at least now) two types of threading, pthreads and Solaris threads. They may not be called Solaris threads, but the point is that thread.h is for a Solaris- (or SunOS-) specific threads implementation. You're probably going to have to convert it to pthreads if you want to run it on another platform. Thanks, Lyle Taylor -----Original Message----- From: Kate Adams [mailto:KateA@xxxxxxxxxxxxxxxx] Sent: Monday, September 29, 2003 4:29 AM To: gcc-help@xxxxxxxxxxx Subject: thread.h not recognised hello all, im trying to run an old college server program (originally used with unix on sun machines) using cygwin on a pc. #include <pthread.h> is fine, but it doesnt let me have #include <thread.h>. if i comment out thread.h then the program runs but it isnt working correctly with the client, can anyone tell me how i can get gcc to be able to include thread.h? i am a very rusty non-expert so sorry if this is a dumbass question. thanks very much, kate