When Emacs loads a Lisp library, it searches for the library
in a list of directories specified by the variable
The value of this variable is a list of directories to search when loading files with
load. Each element is a string (which must be a directory name) or
nil(which stands for the current working directory).
When Emacs starts up, it sets up the value of
in several steps. First, it initializes
default locations set when Emacs was compiled. Normally, this
is a directory something like
(In this and the following examples, replace /usr/local with the installation prefix appropriate for your Emacs.) These directories contain the standard Lisp files that come with Emacs. If Emacs cannot find them, it will not start correctly.
If you run Emacs from the directory where it was built—that is, an
executable that has not been formally installed—Emacs instead
load-path using the lisp
directory in the directory containing the sources from which it
If you built Emacs in a separate directory from the
sources, it also adds the lisp directories from the build directory.
(In all cases, elements are represented as absolute file names.)
Unless you start Emacs with the --no-site-lisp option,
it then adds two more site-lisp directories to the front of
load-path. These are intended for locally installed Lisp files,
and are normally of the form:
The first one is for locally installed files for a specific Emacs version; the second is for locally installed files meant for use with all installed Emacs versions. (If Emacs is running uninstalled, it also adds site-lisp directories from the source and build directories, if they exist. Normally these directories do not contain site-lisp directories.)
If the environment variable EMACSLOADPATH is set, it modifies
the above initialization procedure. Emacs initializes
load-path based on the value of the environment variable.
The syntax of EMACSLOADPATH is the same as used for
directory names are separated by ‘:’ (or ‘;’, on some
Here is an example of how to set EMACSLOADPATH variable (from a
An empty element in the value of the environment variable, whether
trailing (as in the above example), leading, or embedded, is replaced
by the default value of
load-path as determined by the standard
initialization procedure. If there are no such empty elements, then
EMACSLOADPATH specifies the entire
load-path. You must
include either an empty element, or the explicit path to the directory
containing the standard Lisp files, else Emacs will not function.
(Another way to modify
load-path is to use the -L
command-line option when starting Emacs; see below.)
For each directory in
load-path, Emacs then checks to see if
it contains a file subdirs.el, and if so, loads it. The
subdirs.el file is created when Emacs is built/installed,
and contains code that causes Emacs to add any subdirectories of those
load-path. Both immediate subdirectories and
subdirectories multiple levels down are added. But it excludes
subdirectories whose names do not start with a letter or digit, and
subdirectories named RCS or CVS, and subdirectories
containing a file named .nosearch.
Next, Emacs adds any extra load directories that you specify using the -L command-line option (see Action Arguments). It also adds the directories where optional packages are installed, if any (see Packaging Basics).
It is common to add code to one's init file (see Init File) to
add one or more directories to
load-path. For example:
(push "~/.emacs.d/lisp" load-path)
Dumping Emacs uses a special value of
load-path. If you use
a site-load.el or site-init.el file to customize the
dumped Emacs (see Building Emacs), any changes to
that these files make will be lost after dumping.
This command finds the precise file name for library library. It searches for the library in the same way
loaddoes, and the argument nosuffix has the same meaning as in
load: don't add suffixes ‘.elc’ or ‘.el’ to the specified name library.
If the path is non-
nil, that list of directories is used instead of
locate-libraryis called from a program, it returns the file name as a string. When the user runs
locate-libraryinteractively, the argument interactive-call is
t, and this tells
locate-libraryto display the file name in the echo area.
This command shows a list of shadowed Emacs Lisp files. A shadowed file is one that will not normally be loaded, despite being in a directory on
load-path, due to the existence of another similarly-named file in a directory earlier on
For instance, suppose
load-pathis set to("/opt/emacs/site-lisp" "/usr/share/emacs/23.3/lisp")
and that both these directories contain a file named foo.el. Then
(require 'foo)never loads the file in the second directory. Such a situation might indicate a problem in the way Emacs was installed.
When called from Lisp, this function prints a message listing the shadowed files, instead of displaying them in a buffer. If the optional argument
nil, it instead returns the shadowed files as a string.