9.42.3.1 Special Characters

The presence of a ‘#’ appearing anywhere on a line indicates the start of a comment that extends to the end of that line.

If a ‘#’ appears as the first character of a line then the whole line is treated as a comment, but in this case the line can also be a logical line number directive (see Comments) or a preprocessor control command (see Preprocessing).

The ‘;’ character can be used to separate statements on the same line.