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