5.2 Common file syntax

Data files read by these programs are text files that share certain syntax elements:

• Comments begin with a `%' character and continue to the end of the line. The content of comments is entirely ignored.

• Blank lines are allowed, and ignored. Whitespace characters (as defined by the C facility isspace) are ignored at the beginning of a line.

• Any character except ASCII NUL--character zero--is acceptable in data files. (We would allow NULs, too, at the expense of complicating the code, if we knew of any useful purpose for them.)

A line can be as long as you want.