Compilation database as project format
With non-CMake and non-Gradle projects, you can still benefit from the advanced IDE features that CLion provides. One way is to import a non-CMake project and let CLion convert it into a simple CMake structure. Another option is to open a project by loading its compilation database.
A compilation database lets CLion detect project files and extract all the necessary compiler information, such as include paths and compilation flags. This approach enables you to operate in the IDE and get the full experience of its capabilities while keeping your project independent from CMake or Gradle.
The following snippet shows an example of a JSON compilation database:
You can see an array of entries called command objects. Each command object represents the translation unit’s main file, the working directory, the actual compile command (or the list of arguments), and optionally the name of the output created by the compilation step. For more details on the format, see the official documentation.
Generate a compilation database
To get a compilation database for your project, you have a wide variety of options: it can be generated by compilers, build systems, and specialized tools (see the expanded list of variants). Some examples are given below:
Clang (version 5.0 and later):
Ninja (version 1.2 and later):
To get a compilation database, use the -t compdb option. Note that it requires rule names as arguments:
-t compdb rule1 rule2... The list of rules is provided in the Ninja build file (default name build.ninja), for example:
The compiledb-generator tool creates compilation databases for make-based build systems.
Bear and intercept-build tools:
SourceTrail Visual Studio extension:
Work with compilation database in CLion
Load a project
Once you have created a compilation database for your project, you can load it in CLion. Navigate to compile_commands.json file or a directory that contains it, and click Open as Project.on the main menu, choose the
As a result, the project files are detected and the status of all commands in compile_commands.json is shown in the Build tool window:
Now CLion's code insight, refactoring, analysis, and navigation are fully available for your project.
CLion natively supports JSON file format, so you can edit the compile_database.json file right in the IDE, with highlighting and code completion for help. Also, CLion checks the compliance of your compile_database.json file with the compilation database JSON schema. For example, it notices when a property is missing in a command entry, or when you use a wrong type:
Change project root
By default, the project root is set to the directory containing the compilation database file. However, this is not always convenient: for example, if some project files are located outside of the directory with compile_commands.json (i.e., out of the project root), such files are listed in the tree regardless the actual folder structure. In this case, you need to set the project root to the parent directory containing both compile_commands.json and the project files.
To change the project root, selectfrom the main menu, and provide a different location for the project root.
Auto-import and project reload
To have your project automatically reloaded for every change in compile_command.json, set the Use auto-import checkbox in . If the checkbox is cleared, a pop-up message prompting to import changes will be shown upon any modification of the compilation database file:
You can also use the Reload Compilation Database Project action from the menu to refresh the project manually when needed.
Compile a single file
Although the build functionality for compilation database projects is not yet implemented in CLion, you may find it useful to check the changes in a single file without building the whole project. For this purpose, CLion provides the Recompile action. It is available for individual source and header files, and also for groups of files selected in the project tree. For headers, CLion uses resolve context to compile one of the source files that include the specified header. Note that Recompile is disabled for directories and non-C/C++ files.
To call Recompile for the currently opened file, choose from the main menu (or press Ctrl+Shift+F9). For a file in the project tree, use the Recompile option from the right-click menu (or press the same Ctrl+Shift+F9 keys). To recompile several files, select them in the project tree, and use the Recompile selected files option from the right-click menu Ctrl+Shift+F9. Note that when used for multiple files, the recompilation stops upon the first compilation failure.
When you Recompile a file, CLion extracts necessary information from the corresponding command object in compile_commands.json: the compilation command line (yet CLion suppresses the output and removes the flags that specify output files), and the compiler to be used.