This function returns the name of the file that defined symbol.
If type is
nil, then any kind of definition is acceptable.
If type is
specifies function definition, variable definition, or face definition
The value is normally an absolute file name. It can also be
if the definition is not associated with any file. If symbol
specifies an autoloaded function, the value can be a relative file name
The basis for
symbol-file is the data in the variable
The value of this variable is an alist that associates the names of loaded library files with the names of the functions and variables they defined, as well as the features they provided or required.
Each element in this alist describes one loaded library (including libraries that are preloaded at startup). It is a list whose CAR is the absolute file name of the library (a string). The rest of the list elements have these forms:
The symbol var was defined as a variable.
(defun . fun)
The function fun was defined.
(t . fun)
The function fun was previously an autoload before this library
redefined it as a function. The following element is always
(defun . fun), which represents defining fun as a
(autoload . fun)
The function fun was defined as an autoload.
(defface . face)
The face face was defined.
(require . feature)
The feature feature was required.
(provide . feature)
The feature feature was provided.
(cl-defmethod method specializers)
The named method was defined by using
specializers as its specializers.
(define-type . type)
The type type was defined.
The value of
load-history may have one element whose CAR is
nil. This element describes definitions made with
eval-buffer on a buffer that is not visiting a file.
load-history, but does so
by adding the symbols defined to the element for the file being visited,
rather than replacing that element. See Eval.