"D. R. Evans" <doc.evans@xxxxxxxxx> wrote: > > Is there a clear description anywhere of how to use C++ streams and > ordinary C FILE* functions so that they don't fail when an attempt to write > to a file goes past the 2GB boundary? No. I can't begin to describe how messed up this area is. I could start with K&R C and AT&T Unix (which had excuses), ISO C and POSIX (which didn't) and carry on from there. The one thing that I can say is that the compiler (i.e. gcc, sensu stricto) has nothing to do with the matter. This is entirely a library and operating system issue and, by the sound of it, you are knackered. You can try creating such a file using the underlying POSIX calls and see if that works. You may need to specify O_LARGEFILE in the open call. Regards, Nick Maclaren, University of Cambridge Computing Service, New Museums Site, Pembroke Street, Cambridge CB2 3QH, England. Email: nmm1@xxxxxxxxx Tel.: +44 1223 334761 Fax: +44 1223 334679