How do I search Info for help on a given keyword or function?

Question

Occasionally looking up a function with C-h f will cross reference to an Info node in the manual, but that is pretty rare. I often want a way to jump from the help documentation on a given function to the corresponding documentation referencing it in Info, but I have yet to find an easy way to do that. info-finder can sort of work on categories, and of course it's possible to manually search through various Info manuals from the root menu at C-h i.

I have found info-apropos, which can be a little slow. It appears to read and index every Info file for every keyword search. Is there a better or faster method for looking up a keyword in Info? Is there a way to pre-index info-apropos? Is there a nice way to jump from the help for a function to related Info pages?

Answer 1

In addition to info-lookup-symbol (C-h S), if you use library help-fns+.el then C-h f, C-h v, or C-h k includes a link to look up the function (or variable etc.) in the manuals (using the index).

You control which manuals are searched by way of user option help-cross-reference-manuals. The default behavior is to look in the Emacs and Elisp manuals.

See Links to Manuals.

Answer 2

info-lookup-symbol bound by default to C-h S can search info indices to find the relevant node for symbol corresponding to point.

Answer 3

I have since found that elisp-index-search and emacs-index-search are also quite useful. They search for indexed topics in the Emacs Lisp Reference Manual or the Emacs User Manual respectively.