 <p><a href="http://www.cplusplus.com/forum/general/33653/">http://www.cplusplus.com/forum/general/33653/</a></p> <p>You can add the "\" anywhere in the code and newline will be ignored.</p> <p>As a better reference the 2.2 paragraph of the standard:</p> <blockquote> <p>Each instance of a backslash character () immediately followed by a new-line character is deleted, splicing physical source lines to form logical source lines. Only the last backslash on any physical source line shall be eligible for being part of such a splice. If, as a result, a character sequence that matches the syntax of a universal-character-name is produced, the behavior is undefined. A source file that is not empty and that does not end in a new-line character, or that ends in a new-line character immediately preceded by a backslash character before any such splicing takes place, shall be processed as if an additional new-line character were appended to the file.</p> </blockquote> <p>This is not clear regarding what happens if the last character in the file is a backslash. In such a case, presumably the result of adding the newline should not be a line splice but rather a backslash preprocessing-token (that will be diagnosed as an invalid token in phase 7), but that should be spelled out.</p>