4.6.5.10 Footnotes

A footnote is typically anchored to a place in the text with a marker, which is a small integer, a symbol such as a dagger, or arbitrary user-specified text.

String: \*[*]

Place an automatic number, an automatically generated numeric footnote marker, in the text. Each time this string is interpolated, the number it produces increments by one. Automatic numbers start at 1. This is a Berkeley extension.

Enclose the footnote text in FS and FE macro calls to set it at the nearest available “foot”, or bottom, of a text column or page.

Macro: .FS [marker]

Macro: .FE

Begin (FS) and end (FE) a footnote. FS calls FS-MARK with any supplied marker argument, which is then also placed at the beginning of the footnote text. If marker is omitted, the next pending automatic footnote number enqueued by interpolation of the * string is used, and if none exists, nothing is prefixed.

You may not desire automatically numbered footnotes in spite of their convenience. You can indicate a footnote with a symbol or other text by specifying its marker at the appropriate place (for example, by using \[dg] for the dagger glyph) and as an argument to the FS macro. Such manual marks should be repeated as arguments to FS or as part of the footnote text to disambiguate their correspondence. You may wish to use \*{ and \*} to superscript the marker at the anchor point, in the footnote text, or both.

groff ms provides a hook macro, FS-MARK, for user-determined operations to be performed when the FS macro is called. It is passed the same arguments as FS itself. An application of FS-MARK is anchor placement for a hyperlink reference, so that a footnote can link back to its referential context.¹¹ By default, this macro has an empty definition. FS-MARK is a GNU extension.

Footnotes can be safely used within keeps and displays, but you should avoid using automatically numbered footnotes within floating keeps. You can place a second \** interpolation between a \** and its corresponding FS call as long as each FS call occurs after the corresponding \** and occurrences of FS are in the same order as corresponding occurrences of \**.

Footnote text is formatted as paragraphs are, using analogous parameters. The registers FI, FPD, FPS, and FVS correspond to PI, PD, PS, and CS, respectively; FPD, FPS, and FVS are GNU extensions.

The FF register controls the formatting of automatically numbered footnote paragraphs and those for which FS is given a marker argument. See ms Document Control Settings.

The default footnote line length is 11/12ths of the normal line length for compatibility with the expectations of historical ms documents; you may wish to set the FR string to ‘1’ to align with contemporary typesetting practices. In the past,¹² an FL register was used for the line length in footnotes; however, setting this register at document initialization time had no effect on the footnote line length in multi-column arrangements.¹³

FR should be used in preference to the old FL register in contemporary documents. The footnote line length is effectively computed as ‘column-width * \*[FR]’. If an absolute footnote line length is required, recall that arithmetic expressions in roff input are evaluated strictly from left to right, with no operator precedence (parentheses are honored).

.ds FR 0+3i \" Set footnote line length to 3 inches.