locate-file function not found in Emacs?

I want to use the locate-file function in Emacs to find files qui开发者_Python百科ckly using file names. This link: http://www.gnu.org/software/emacs/elisp/html_node/Locating-Files.html says that there is a command function 'locate-file' for this purpose.

But when I try to use this function using: M-x locate-file it says [No match]. What could be the problem?

Strangely, when the function is present in describe-function!

Use icicle-locate or icicle-locate-file, in Icicles.

If you are on GNU/Linux or Unix then use icicle-locate, which takes advantage of the OS command locate, which uses a periodically updated index created by the OS command updatedb. Because of such indexing, locate (and hence icicle-locate) is extremely fast. And because this is Icicles you get the same incremental pattern matching you see in Anything (and more).

locate-file is not for interactive use. There are lots of tools for finding files like dired-find.