ClangFormat and Notepad ++ Integration

ClangFormat is one of the best tools for automatically formatting source codes in C, C ++, Java, JavaScript, Objective-C, C #. There are plugins for popular development environments (IDEs), but often you need to quickly format a file or part of a source file without launching a cumbersome IDE, experiment with formatting settings and different versions of ClangFormat with the ability to quickly undo changes. Using the console version of ClangFormat for this purpose is inconvenient. A possible solution is to call ClangFormat from a text editor. The official website describes integration methods with Vim, Emacs, and some others, but there is no information on integration with Notepad ++. The following is a simple instruction for Notepad ++ (for Windows).

Initial requirements

  • formatting a file opened in Notepad ++ using ClangFormat;
  • formatting the selected fragment in the file;
  • discard changes;
  • switching style (set of rules) formatting;
  • Switching to another version of ClangFormat
  • use standard tools whenever possible, without rebuilding ClangFormat and without writing a new plugin for Notepad ++.

Installation and setup

1. If Notepad ++ is not already installed, download and install it

2. In Notepad ++ install the NppExec plugin

NppExec allows you to call third-party applications from Notepad ++ and interact with the components of the Scintilla library, based on which Notepad ++ is written.

Plugins –> Plugin Admin... –> NppExec –> Install
Notepad ++ will restart, after which the directory /plugins/NppExec/and menu item will appearPlugins –> NppExec

3. Download the ClangFormat executable

To do this, on the page we find and download the installation file for Windows, for example LLVM-X.X.X-rYYYYYY-win64.exe. You can not install the whole package, just extract the file with the archiver clang-format.exe. You can use 7-zip: delete the extension from the file .exe, open the file with 7-zip and extract the bin/file from the subdirectory clang-format.exe. We put the file clang-format.exein the directory /plugins/NppExec/clang-format/.

4. Add configuration files for ClangFormat

Configuration files must have the name .clang-formator _clang-format. They contain a set of formatting rules (styles), the format of which is described in the ClangFormat Style Options guide .

For example, we use files from the Linux Kernel and Qt projects .

The files downloaded from GitHub are .clang-formatplaced in the appropriate directories:

5. Create a script for NppExec

Open the window for editing and running NppExec scripts Plugins –> NppExec –> Execute...or click F6. Copy and paste the script text below into the window and save the script under the name of the clang-formatbutton Save....

NppExec script
// Hide console
// Uncomment a line to select a style
//set style = LINUX_KERNEL
set style = QT
set clangformatexe = $(CWD)\plugins\NppExec\clang-format\clang-format.exe
set clangformatcfgdir = $(CWD)\plugins\NppExec\clang-format
set tmpdir = $(SYS.TEMP)
set clangformatcfgfile = $(clangformatcfgdir)\$(style)\.clang-format
set srcfiletmp = $(tmpdir)\~src.tmp
cmd.exe /c if exist "$(clangformatexe)" (exit 0) else (exit 1)
if $(EXITCODE) != 0 then
    echo ERROR: "$(clangformatexe)" not found
cmd.exe /c if exist "$(clangformatcfgfile)" (exit 0) else (exit 1)
if $(EXITCODE) != 0 then
    echo ERROR: "$(clangformatcfgfile)" not found
// Copy $(clangformatcfgfile) to $(tmpdir)\.clang-format if their temestamps are different
cmd.exe /v /c " for %i in ("$(clangformatcfgfile)") do set date1="%~ti" && for %i in ("$(tmpdir)\.clang-format") do set date2="%~ti" && if not "!date1!"=="!date2!" ( echo !date1! != !date2! && echo COPYING $(clangformatcfgfile) to $(tmpdir)\ && copy "$(clangformatcfgfile)" "$(tmpdir)\" /Y )"
if $(EXITCODE) != 0 then
    echo ERROR copying "$(clangformatcfgfile)" to "$(tmpdir)"
// Get selected text length
sci_sendmsg SCI_GETSELTEXT
// If nothing is selected - select the current line
if $(MSG_RESULT) == 1 then
    sci_sendmsg SCI_VCHOMEWRAP
// Save selected text to $(srcfiletmp)
sel_saveto "$(srcfiletmp)" :a
cmd.exe /c if exist "$(srcfiletmp)" (exit 0) else (exit 1)
if $(EXITCODE) != 0 then
    echo ERROR: "$(srcfiletmp)" not found
// Run ClangFormat
$(clangformatexe) -i -style=file "$(srcfiletmp)"
if $(EXITCODE) != 0 then
    echo ERROR running "$(clangformatexe)"
// Replace selected text with $(srcfiletmp)
sel_loadfrom "$(srcfiletmp)"
// Delete $(srcfiletmp) file
cmd.exe /c del "$(srcfiletmp)"

After starting the script, on the basis of the selected formatting style specified in the variable style, selects the desired file .clang-format, checks the date of its change and, if necessary, copies it to the temporary directory. There, the selected fragment of the source code is copied to the temporary file, and then it is launched clang-format.exe. The formatted fragment is copied back to the Notepad ++ window. Then the temporary file is deleted.

In ClangFormat there is no way to specify the path to the configuration file .clang-format. ClangFormat will search for it in the directory of the formatted file and, if it does not find it, it will go to search in the parent directories. After the script finishes, the file .clang-formatwill remain in the temporary directory in order not to copy it each time formatting is started.

At all stages of the script, errors are checked, and when they occur, the NppExec console window opens, in which a message is displayed.

6. In Notepad ++, add a new menu item to run the script

Open Plugins –> NppExec –> Advanced Options..., Associated scriptselect the script name in the drop-down list clang-formatand click on the button Add/Modify.

We restart Notepad ++, after which the menu item appears Plugins –> NppExec –> clang-format.


7. In Notepad ++, configure the keyboard shortcut for running the script

We will use a combination Ctrl + Isimilar to QtCreator. We open Settings –> Shortcut Mapper.

By default, the combination is Ctrl + Ibusy, so you need to release it with the button Clearin the tab Main Menu(line 38 Split Linesin the current version of Notepad ++). After that, in the tab we Plugin commandsassign a combination Ctrl + Ito the script clang-format.

Done, we can use it!

Instruction for use

Open the source file in Notepad ++, select the desired fragment or all the text and click Ctrl + I. If nothing is selected, the current line will be formatted.


To undo changes, use the standard editor tools ( Ctrl + Z).
To change formatting rules, edit the configuration files .clang-formatin the directory. /plugins/NppExec/clang-format/
If you need to use a different version of ClangFormat, then change the path to the executable file in the script.
set clangformat = "\path\to\clang-format.exe"
To select a different formatting style, click F6and clang-formatselect the desired style in the script text by uncommenting one of the lines
set style = STYLE_NAME.

All necessary files are in the archive .

Good formatting!

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