(defun locate-file (filename path &optional suffixes predicate)
"Search for FILENAME through PATH.
+If found, return the absolute file name of FILENAME, with its suffixes;
+otherwise return nil.
+PATH should be a list of directories to look in, like the lists in
+`exec-path' or `load-path'.
If SUFFIXES is non-nil, it should be a list of suffixes to append to
file name when searching. If SUFFIXES is nil, it is equivalent to '(\"\").
+Use '(\"/\") to disable PATH search, but still try the suffixes in SUFFIXES.
If non-nil, PREDICATE is used instead of `file-readable-p'.
PREDICATE can also be an integer to pass to the `access' system call,
in which case file-name handlers are ignored. This usage is deprecated.