http://gcc.gnu.org/bugzilla/show_bug.cgi?id=8270
--- Comment #51 from GoWhoopee at yahoo dot com --- http://web.cs.dal.ca/~vlado/pl/C_Standard_2011-n1570.pdf That's the principle, but not what happens with gcc... Phase 2 says, "Each instance of a backslash character (\) immediately followed by a newline character is deleted, splicing physical source lines to form logical source lines.", and explicitly states that, "Only the last backslash on any physical source line shall be eligible for such a splice.". I wonder if all trailing white-space is being trimmed from each source line before or during the first Translation Phase?