5.1.3 Sentences

Although it is often debated, some typesetting rules say there should be different amounts of space after various punctuation marks. For example, the Chicago typsetting manual says that a period at the end of a sentence should have twice as much space following it as would a comma or a period as part of an abbreviation.

gtroff does this by flagging certain characters (normally ‘!’, ‘?’, and ‘.’) as end-of-sentence characters. When gtroff encounters one of these characters at the end of a line, it appends a normal space followed by a sentence space in the formatted output. (This justifies one of the conventions mentioned in Input Conventions.)

In addition, the following characters and symbols are treated transparently while handling end-of-sentence characters: ‘"’, ‘'’, ‘)’, ‘]’, ‘*’, \[dg], \[rq], and \[cq].

See the cflags request in Using Symbols, for more details.

To prevent the insertion of extra space after an end-of-sentence character (at the end of a line), append \&.