10.5 Printing Indices and Menus

To print an index means to include it as part of a manual or Info file. This does not happen automatically just because you use @cindex or other index-entry generating commands in the Texinfo file; those just cause the raw data for the index to be accumulated. To generate an index, you must include the @printindex command at the place in the document where you want the index to appear. Also, as part of the process of creating a printed manual, you must run a program called texindex (see Formatting and Printing Hardcopy) to sort the raw data to produce a sorted index file. The sorted index file is what is actually used to print the index.

Texinfo offers six separate types of predefined index, which suffice in most cases. See the other parts of this chapter for information on this, as well as advanced indexing commands, defining your own new indices, combining indices, and, most importantly, advice on writing the actual index entries. This section focuses on printing indices, which is done with the @printindex command.

@printindex takes one argument, a two-letter index abbreviation. It reads the corresponding sorted index file (for printed output), and formats it appropriately into an index.

The @printindex command does not generate a chapter heading for the index, since different manuals have different needs. Consequently, you should precede the @printindex command with a suitable section or chapter command (usually @appendix or @unnumbered) to supply the chapter heading and put the index into the table of contents. Precede the chapter heading with an @node line as usual.

For example:

@node Variable Index
@unnumbered Variable Index

@printindex vr

@node Concept Index
@unnumbered Concept Index

@printindex cp

If you have more than one index, we recommend placing the concept index last.

• In printed output, @printindex produces a traditional two-column index, with dot leaders between the index terms and page numbers.
• In Info output, @printindex produces a special menu containing the line number of the entry, relative to the start of the node. Info readers can use this to go to the exact line of an entry, not just the containing node. (Older Info readers will just go to the node.) Here’s an example:

  * First index entry:   Top.   (line  7)
  

  The actual number of spaces is variable, to right-justify the line number; it’s been reduced here to make the line fit in the printed manual.

• In plain text output, @printindex produces the same menu, but the line numbers are relative to the start of the file, since that’s more convenient for that format.
• In HTML output, @printindex produces links to the index entries.
• In XML and DocBook output, it simply records the index to be printed.