i want to use my own printf,but i must use the other function declared in stdio.h,there is always an error"previous defined",how can i solve the problem. another question,how can i build the cygwin1.dll?any reference or document here? thanks. _________________________________________________________________ The new MSN 8: smart spam protection and 2 months FREE* http://join.msn.com/?page=features/junkmail -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/