What version do You use? I find Apple's "clang masquerading as gcc" compiler on a Mac OS system retains the spaces while linux versions as recent as gcc 4.9 (development) instead discard the spaces. -- View this message in context: http://gcc.1065356.n5.nabble.com/Spaces-in-macro-expansion-in-a-include-tp1022862p1022868.html Sent from the gcc - Help mailing list archive at Nabble.com.