Standard Pascal requires that all characters written to a file should appear when the file is read (the exception to this is that implementations are allowed to designate a set of characters as prohibited from text files and treat these characters specially). The Windows, DOS, and OS/2 editions of Irie Pascal do not comply fully with this requirement, since with these editions carriage-return characters do not appear when individual characters are read from text files. This treatment of carriage-return characters is intended to convert carriage-return/line-feed pairs (that are used as end-of-line markers in some text files) into a single end-of-line character (i.e. a line-feed chr(10)).