Preprocessing

• Preprocessing handles macro substitution, conditional compilation, and file inclusion.

• Preprocessing replaces trigraph sequences with their single-character equivalents, partitions source files into preprocessing tokens, and executes preprocessing directives.

• Lines that end with a backslash character ``\'' and new-line are joined with the next line by deleting the backslash and the new-line characters, so that each line in the source file is a logical line. This occurs (in translation phase 2) before input is divided into tokens.

• Lines beginning with # are preprocessing directives. Spaces and tabs may appear before and after the #.

• Each preprocessing directive must appear on a logical line by itself.