cc-other-file-alist

cc-other-file-alist is a variable defined in `find-file.el'.
Its value is shown below.

Documentation:
Alist of extensions to find given the current file's extension.

This list should contain the most used extensions before the others,
since the search algorithm searches sequentially through each directory
specified in `ff-search-directories'. If a file is not found, a new one
is created with the first matching extension (`.cc' yields `.hh').

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.4 of Emacs.

Value:

(("\\.cc\\'"
  (".hh" ".h"))
 ("\\.hh\\'"
  (".cc" ".C"))
 ("\\.c\\'"
  (".h"))
 ("\\.m\\'"
  (".h"))
 ("\\.h\\'"
  (".c" ".cc" ".C" ".CC" ".cxx" ".cpp" ".m"))
 ("\\.C\\'"
  (".H" ".hh" ".h"))
 ("\\.H\\'"
  (".C" ".CC"))
 ("\\.CC\\'"
  (".HH" ".H" ".hh" ".h"))
 ("\\.HH\\'"
  (".CC"))
 ("\\.c\\+\\+\\'"
  (".h++" ".hh" ".h"))
 ("\\.h\\+\\+\\'"
  (".c++"))
 ("\\.cpp\\'"
  (".hpp" ".hh" ".h"))
 ("\\.hpp\\'"
  (".cpp"))
 ("\\.cxx\\'"
  (".hxx" ".hh" ".h"))
 ("\\.hxx\\'"
  (".cxx")))