1===========
2ClangFormat
3===========
4
5`ClangFormat` describes a set of tools that are built on top of
6:doc:`LibFormat`. It can support your workflow in a variety of ways including a
7standalone tool and editor integrations.
8
9
10Standalone Tool
11===============
12
13:program:`clang-format` is located in `clang/tools/clang-format` and can be used
14to format C/C++/Obj-C code.
15
16.. code-block:: console
17
18  $ clang-format -help
19  OVERVIEW: A tool to format C/C++/Java/JavaScript/Objective-C/Protobuf code.
20
21  If no arguments are specified, it formats the code from standard input
22  and writes the result to the standard output.
23  If <file>s are given, it reformats the files. If -i is specified
24  together with <file>s, the files are edited in-place. Otherwise, the
25  result is written to the standard output.
26
27  USAGE: clang-format [options] [<file> ...]
28
29  OPTIONS:
30
31  Clang-format options:
32
33    -assume-filename=<string> - When reading from stdin, clang-format assumes this
34                                filename to look for a style config file (with
35                                -style=file) and to determine the language.
36    -cursor=<uint>            - The position of the cursor when invoking
37                                clang-format from an editor integration
38    -dump-config              - Dump configuration options to stdout and exit.
39                                Can be used with -style option.
40    -fallback-style=<string>  - The name of the predefined style used as a
41                                fallback in case clang-format is invoked with
42                                -style=file, but can not find the .clang-format
43                                file to use.
44                                Use -fallback-style=none to skip formatting.
45    -i                        - Inplace edit <file>s, if specified.
46    -length=<uint>            - Format a range of this length (in bytes).
47                                Multiple ranges can be formatted by specifying
48                                several -offset and -length pairs.
49                                When only a single -offset is specified without
50                                -length, clang-format will format up to the end
51                                of the file.
52                                Can only be used with one input file.
53    -lines=<string>           - <start line>:<end line> - format a range of
54                                lines (both 1-based).
55                                Multiple ranges can be formatted by specifying
56                                several -lines arguments.
57                                Can't be used with -offset and -length.
58                                Can only be used with one input file.
59    -offset=<uint>            - Format a range starting at this byte offset.
60                                Multiple ranges can be formatted by specifying
61                                several -offset and -length pairs.
62                                Can only be used with one input file.
63    -output-replacements-xml  - Output replacements as XML.
64    -sort-includes            - Sort touched include lines
65    -style=<string>           - Coding style, currently supports:
66                                  LLVM, Google, Chromium, Mozilla, WebKit.
67                                Use -style=file to load style configuration from
68                                .clang-format file located in one of the parent
69                                directories of the source file (or current
70                                directory for stdin).
71                                Use -style="{key: value, ...}" to set specific
72                                parameters, e.g.:
73                                  -style="{BasedOnStyle: llvm, IndentWidth: 8}"
74
75  Generic Options:
76
77    -help                     - Display available options (-help-hidden for more)
78    -help-list                - Display list of available options (-help-list-hidden for more)
79    -version                  - Display the version of this program
80
81
82When the desired code formatting style is different from the available options,
83the style can be customized using the ``-style="{key: value, ...}"`` option or
84by putting your style configuration in the ``.clang-format`` or ``_clang-format``
85file in your project's directory and using ``clang-format -style=file``.
86
87An easy way to create the ``.clang-format`` file is:
88
89.. code-block:: console
90
91  clang-format -style=llvm -dump-config > .clang-format
92
93Available style options are described in :doc:`ClangFormatStyleOptions`.
94
95
96Vim Integration
97===============
98
99There is an integration for :program:`vim` which lets you run the
100:program:`clang-format` standalone tool on your current buffer, optionally
101selecting regions to reformat. The integration has the form of a `python`-file
102which can be found under `clang/tools/clang-format/clang-format.py`.
103
104This can be integrated by adding the following to your `.vimrc`:
105
106.. code-block:: vim
107
108  map <C-K> :pyf <path-to-this-file>/clang-format.py<cr>
109  imap <C-K> <c-o>:pyf <path-to-this-file>/clang-format.py<cr>
110
111The first line enables :program:`clang-format` for NORMAL and VISUAL mode, the
112second line adds support for INSERT mode. Change "C-K" to another binding if
113you need :program:`clang-format` on a different key (C-K stands for Ctrl+k).
114
115With this integration you can press the bound key and clang-format will
116format the current line in NORMAL and INSERT mode or the selected region in
117VISUAL mode. The line or region is extended to the next bigger syntactic
118entity.
119
120It operates on the current, potentially unsaved buffer and does not create
121or save any files. To revert a formatting, just undo.
122
123
124Emacs Integration
125=================
126
127Similar to the integration for :program:`vim`, there is an integration for
128:program:`emacs`. It can be found at `clang/tools/clang-format/clang-format.el`
129and used by adding this to your `.emacs`:
130
131.. code-block:: common-lisp
132
133  (load "<path-to-clang>/tools/clang-format/clang-format.el")
134  (global-set-key [C-M-tab] 'clang-format-region)
135
136This binds the function `clang-format-region` to C-M-tab, which then formats the
137current line or selected region.
138
139
140BBEdit Integration
141==================
142
143:program:`clang-format` cannot be used as a text filter with BBEdit, but works
144well via a script. The AppleScript to do this integration can be found at
145`clang/tools/clang-format/clang-format-bbedit.applescript`; place a copy in
146`~/Library/Application Support/BBEdit/Scripts`, and edit the path within it to
147point to your local copy of :program:`clang-format`.
148
149With this integration you can select the script from the Script menu and
150:program:`clang-format` will format the selection. Note that you can rename the
151menu item by renaming the script, and can assign the menu item a keyboard
152shortcut in the BBEdit preferences, under Menus & Shortcuts.
153
154
155Visual Studio Integration
156=========================
157
158Download the latest Visual Studio extension from the `alpha build site
159<http://llvm.org/builds/>`_. The default key-binding is Ctrl-R,Ctrl-F.
160
161
162Script for patch reformatting
163=============================
164
165The python script `clang/tools/clang-format-diff.py` parses the output of
166a unified diff and reformats all contained lines with :program:`clang-format`.
167
168.. code-block:: console
169
170  usage: clang-format-diff.py [-h] [-i] [-p NUM] [-regex PATTERN] [-style STYLE]
171
172  Reformat changed lines in diff. Without -i option just output the diff that
173  would be introduced.
174
175  optional arguments:
176    -h, --help      show this help message and exit
177    -i              apply edits to files instead of displaying a diff
178    -p NUM          strip the smallest prefix containing P slashes
179    -regex PATTERN  custom pattern selecting file paths to reformat
180    -style STYLE    formatting style to apply (LLVM, Google, Chromium, Mozilla,
181                    WebKit)
182
183So to reformat all the lines in the latest :program:`git` commit, just do:
184
185.. code-block:: console
186
187  git diff -U0 HEAD^ | clang-format-diff.py -i -p1
188
189In an SVN client, you can do:
190
191.. code-block:: console
192
193  svn diff --diff-cmd=diff -x-U0 | clang-format-diff.py -i
194
195The :option:`-U0` will create a diff without context lines (the script would format
196those as well).
197