Using clang format

LArSoft has adopted clang-format as a code-formatting tool to ensure a uniform code layout.

Using clang format in the UPS environment

• setup your working environment
• setup cetmodules v3_24_01
  • Any sufficiently modern release of cetmodules (v3_24_01 or later) will work.
• format-code <file or subdirectory>
  • format-code is found in cetmodules and will be using clang v15_0_7

Using clang format with an editor

NOTE: These instructions are old and do not reflect the current clang format.

Although clang-format can be made available by explicitly setting up the clang UPS product, the recommended way of using clang-format is to integrate it into your editor.

Prerequisites

To use the UPS-provided clang-format utility inside the editors, it is necessary that UPS is setup for your file-editing session. If UPS has been setup, then you should see the following when typed in your shell:

type ups >& /dev/null && echo UPS available
UPS available

If UPS is not found or Clang 7 is not installed in the UPS area, then you will not have access to the clang-format commands within the editors.

Supported editors

• Emacs

Download attachment:ups-claing-format-v7.el and place it in a directory <my_dir>.

Add the following commands to your .emacs file:

(add-to-list 'load-path "<my_dir>")
(load "ups-clang-format-v7")

This will allow you to use the 'M-x clang-format-buffer' and 'M-x clang-format-region' commands while editing files.

• VIM
  • Download attachment:ups-clang-format-v7.vim and place it in your ~/.vim/plugin/ subdirectory.
  • You can then use 'Ctrl-k' while editing files to apply clang-format to the selected line or region.

Expected behavior

For the files being edited, the clang-format commands will use the .clang-format file that is closest to the file. In other words, assume a file has the full path:

/dir1/dir2/dir3/my_file.cpp

and that each of the directories dir1, dir2, and dir3 have .clang-format files. clang-format will choose the .clang-format file located in dir3 as the style to apply to the code in my_file.cpp. If dir3 does not have a .clang-format file, then clang-format will search for a .clang-format file in dir2, and so on. If a .clang-format file cannot be found in the directory hierarchy, then clang-format applies its own default.