It really seems almost impossible :( I wanna only to get convinient debugging tool. All that I want now - to explore and change some part of C++ compiler's code (at 'parsing' and 'tree' levels) - I want to implement my own interface (GUI - for convinient purposes), that will control middle-end. Maybe gdb is really convinient tool, but I wasnt experienced in using it. It will be great if you'll advise how to conviniently debug GCC under cygwin. PS: We can build several GCC's parts (I tried to build cc1plus) under MSVC in one case: If we previously used cygwin to build it, and then, after creating obj directory, use generated *.h, *.c files. I nearly could do it - I compiled all files, that compiled in gcc's cc1plus build except libcpp's and libintl's files. -- Best regards, Alexander mailto:a.shabanov@xxxxxxxxxxxxxxxxxxxxxx