Add clang-format configuration

config.org

@@ -1186,6 +1186,40 @@
      (add-hook 'rust-mode-hook 'cargo-minor-mode)
    #+end_src
 
+** clang-format
+   Most of the time, =lsp-mode= is fine for formatting, but sometimes
+   it doesn't work (mostly just because I haven't gone through the
+   effort to set it up) but I still want to be able to auto-format
+   code easily (that is to say, with a convenient keybinding). The
+   =clang-format= package provides Elisp functions for invoking it.
+
+   #+begin_src emacs-lisp
+     (use-package clang-format)
+   #+end_src
+
+   I want a keybinding that formats the region if its active, or the
+   whole buffer otherwise. It seems that there's no function which
+   does that out of the box, so that has to be defined first:
+
+   #+begin_src emacs-lisp
+     (defun clang-format-region-or-buffer ()
+       "Format the region if it's active, otherwise format the entire buffer."
+         (interactive)
+         (if (region-active-p)
+             (clang-format-region)
+           (clang-format-buffer)))
+   #+end_src
+
+   With that defined, the keybinding can be added to C mode.
+
+   #+begin_src emacs-lisp
+     (add-hook
+      'c-mode-hook
+      (lambda ()
+        (define-key c-mode-map (kbd "C-M-f")
+          'clang-format-region-or-buffer)))
+   #+end_src
+
 * Backup and Autosave
 ** Keep $PWD Tidy
    Emacs' default behaviour of dumping temporary files in the current