C Reference Manual Reading Notes: 002 Whitespace, Line Termination, and Lines Length Limits

   The blank(space), end-of-line, VT, FF, HT, and comments are known collectively as whitespace character (WSC). These characters are ignored except insofar as they are used to separate adjacent tokens or when they appera in character constans, string constans, or #include file names. WCS may be used to lay out the C program in a way that is  pleasing to a human reader.

   The end-of-line character or character sequence marks the end of source program lines. In some emplementations, the formatting characters CR, FF, VT additionally terminate source lines, and are called line break characters. Line Termination is important for the recognition of preprocessor control lines.

    A source line can be continued onto the next line by ending the first line with a backslash(/) or with the trigraph ??/. Most C implementation impose a limit on the maximum length of source lines both before and after splicing continuation lines. C89 require to permit logical source lines of at least 509 characters; C99 allows 4095 characters.