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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++/Obj-C 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    -cursor=<uint>           - The position of the cursor when invoking
34                               clang-format from an editor integration
35    -dump-config             - Dump configuration options to stdout and exit.
36                               Can be used with -style option.
37    -i                       - Inplace edit <file>s, if specified.
38    -length=<uint>           - Format a range of this length (in bytes).
39                               Multiple ranges can be formatted by specifying
40                               several -offset and -length pairs.
41                               When only a single -offset is specified without
42                               -length, clang-format will format up to the end
43                               of the file.
44                               Can only be used with one input file.
45    -lines=<string>          - <start line>:<end line> - format a range of
46                               lines (both 1-based).
47                               Multiple ranges can be formatted by specifying
48                               several -lines arguments.
49                               Can't be used with -offset and -length.
50                               Can only be used with one input file.
51    -offset=<uint>           - Format a range starting at this byte offset.
52                               Multiple ranges can be formatted by specifying
53                               several -offset and -length pairs.
54                               Can only be used with one input file.
55    -output-replacements-xml - Output replacements as XML.
56    -style=<string>          - Coding style, currently supports:
57                                 LLVM, Google, Chromium, Mozilla, WebKit.
58                               Use -style=file to load style configuration from
59                               .clang-format file located in one of the parent
60                               directories of the source file (or current
61                               directory for stdin).
62                               Use -style="{key: value, ...}" to set specific
63                               parameters, e.g.:
64                                 -style="{BasedOnStyle: llvm, IndentWidth: 8}"
65
66  General options:
67
68    -help                    - Display available options (-help-hidden for more)
69    -help-list               - Display list of available options (-help-list-hidden for more)
70    -version                 - Display the version of this program
71
72
73When the desired code formatting style is different from the available options,
74the style can be customized using the ``-style="{key: value, ...}"`` option or
75by putting your style configuration in the ``.clang-format`` or ``_clang-format``
76file in your project's directory and using ``clang-format -style=file``.
77
78An easy way to create the ``.clang-format`` file is:
79
80.. code-block:: console
81
82  clang-format -style=llvm -dump-config > .clang-format
83
84Available style options are described in :doc:`ClangFormatStyleOptions`.
85
86
87Vim Integration
88===============
89
90There is an integration for :program:`vim` which lets you run the
91:program:`clang-format` standalone tool on your current buffer, optionally
92selecting regions to reformat. The integration has the form of a `python`-file
93which can be found under `clang/tools/clang-format/clang-format.py`.
94
95This can be integrated by adding the following to your `.vimrc`:
96
97.. code-block:: vim
98
99  map <C-K> :pyf <path-to-this-file>/clang-format.py<cr>
100  imap <C-K> <c-o>:pyf <path-to-this-file>/clang-format.py<cr>
101
102The first line enables :program:`clang-format` for NORMAL and VISUAL mode, the
103second line adds support for INSERT mode. Change "C-K" to another binding if
104you need :program:`clang-format` on a different key (C-K stands for Ctrl+k).
105
106With this integration you can press the bound key and clang-format will
107format the current line in NORMAL and INSERT mode or the selected region in
108VISUAL mode. The line or region is extended to the next bigger syntactic
109entity.
110
111It operates on the current, potentially unsaved buffer and does not create
112or save any files. To revert a formatting, just undo.
113
114
115Emacs Integration
116=================
117
118Similar to the integration for :program:`vim`, there is an integration for
119:program:`emacs`. It can be found at `clang/tools/clang-format/clang-format.el`
120and used by adding this to your `.emacs`:
121
122.. code-block:: common-lisp
123
124  (load "<path-to-clang>/tools/clang-format/clang-format.el")
125  (global-set-key [C-M-tab] 'clang-format-region)
126
127This binds the function `clang-format-region` to C-M-tab, which then formats the
128current line or selected region.
129
130
131BBEdit Integration
132==================
133
134:program:`clang-format` cannot be used as a text filter with BBEdit, but works
135well via a script. The AppleScript to do this integration can be found at
136`clang/tools/clang-format/clang-format-bbedit.applescript`; place a copy in
137`~/Library/Application Support/BBEdit/Scripts`, and edit the path within it to
138point to your local copy of :program:`clang-format`.
139
140With this integration you can select the script from the Script menu and
141:program:`clang-format` will format the selection. Note that you can rename the
142menu item by renaming the script, and can assign the menu item a keyboard
143shortcut in the BBEdit preferences, under Menus & Shortcuts.
144
145
146Visual Studio Integration
147=========================
148
149Download the latest Visual Studio extension from the `alpha build site
150<http://llvm.org/builds/>`_. The default key-binding is Ctrl-R,Ctrl-F.
151
152
153Script for patch reformatting
154=============================
155
156The python script `clang/tools/clang-format-diff.py` parses the output of
157a unified diff and reformats all contained lines with :program:`clang-format`.
158
159.. code-block:: console
160
161  usage: clang-format-diff.py [-h] [-i] [-p NUM] [-regex PATTERN] [-style STYLE]
162
163  Reformat changed lines in diff. Without -i option just output the diff that
164  would be introduced.
165
166  optional arguments:
167    -h, --help      show this help message and exit
168    -i              apply edits to files instead of displaying a diff
169    -p NUM          strip the smallest prefix containing P slashes
170    -regex PATTERN  custom pattern selecting file paths to reformat
171    -style STYLE    formatting style to apply (LLVM, Google, Chromium, Mozilla,
172                    WebKit)
173
174So to reformat all the lines in the latest :program:`git` commit, just do:
175
176.. code-block:: console
177
178  git diff -U0 HEAD^ | clang-format-diff.py -i -p1
179
180In an SVN client, you can do:
181
182.. code-block:: console
183
184  svn diff --diff-cmd=diff -x-U0 | clang-format-diff.py -i
185
186The :option:`-U0` will create a diff without context lines (the script would format
187those as well).
188