Generate Compilation Database (compile_command.json) Using Qmake (not GUI)

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Generate Compilation Database (compile_command.json) using qmake (not GUI)

Discussion Category: Qmake, Compilation Database

When working on a Qt project, generating a compilation database (compile_command.json) is essential for tools like Clang-Tidy, Clang-Format, and other code analysis and refactoring tools. While Qt Creator provides an easy way to generate this database, there are situations where using the command line is necessary. In this article, we will explore how to generate a compilation database using qmake without the GUI.

Before we dive into the process, make sure you have the following:

  • Qt installed on your system
  • qmake executable available in your system's PATH
  • A Qt project set up with a qmake project file (e.g., project.pro)

The compilation database is a JSON file that contains information about the compilation commands used to build your project. This file is used by tools like Clang-Tidy and Clang-Format to analyze and refactor your code. The database contains information such as:

  • The compilation command used
  • The source files compiled
  • The object files generated
  • The include paths used

To generate the compilation database using qmake, follow these steps:

Step 1: Configure qmake to Generate the Compilation Database

Open your project's project.pro file and add the following line to the QMAKE_EXTRA_COMPILERS variable:

QMAKE_EXTRA_COMPILERS += compiler

This will tell qmake to generate the compilation database.

Step 2: Run qmake to Generate the Compilation Database

Run the following command in your terminal:

qmake -r

This will regenerate the project's build files and generate the compilation database.

Step 3: Verify the Compilation Database

After running qmake, verify that the compilation database has been generated by checking the presence of a compile_commands.json file in your project's build directory.

Let's consider an example project with a project.pro file:

TEMPLATE = app
TARGET = myapp

SOURCES += main.cpp
SOURCES += myclass.cpp


HEADERS += myclass.h


QMAKE_EXTRA_COMPILERS += compiler

To generate the compilation database, run the following command:

qmake -r

This will generate a compile_commands.json file in the project's build directory, containing information about the compilation commands used to build the project.

In this article, we explored how to generate a compilation database using qmake without the GUI. By following the steps outlined above, you can generate a compilation database for your Qt project, enabling tools like Clang-Tidy and Clang-Format to analyze and refactor your code. Remember to configure qmake to generate the compilation database and run qmake to regenerate the project's build files and generate the compilation database.

For more information on using qmake and generating compilation databases, refer to the following resources:

By following the steps outlined in this article and exploring the additional resources provided, you can effectively use qmake to generate a compilation database for your Qt project.
Q&A: Generating Compilation Database (compile_command.json) using qmake (not GUI)

Discussion Category: Qmake, Compilation Database

In our previous article, we explored how to generate a compilation database (compile_command.json) using qmake without the GUI. In this article, we will answer some frequently asked questions related to generating compilation databases using qmake.

A: A compilation database is a JSON file that contains information about the compilation commands used to build your project. This file is used by tools like Clang-Tidy and Clang-Format to analyze and refactor your code. You need a compilation database to enable these tools to work effectively with your project.

A: To configure qmake to generate the compilation database, add the following line to your project's project.pro file:

QMAKE_EXTRA_COMPILERS += compiler

This will tell qmake to generate the compilation database.

A: qmake is used to generate the project's build files, while qmake -r is used to regenerate the project's build files and generate the compilation database.

A: The compilation database file is located in your project's build directory, with the name compile_commands.json.

A: No, qmake is a Qt-specific build system, and it is not compatible with CMake. If you are using CMake to build your Qt project, you will need to use CMake's built-in support for generating compilation databases.

A: If you are experiencing issues with generating the compilation database, try the following:

  • Check that you have added the QMAKE_EXTRA_COMPILERS variable to your project's project.pro file.
  • Verify that you are running qmake -r to regenerate the project's build files and generate the compilation database.
  • Check that the compilation database file is being generated in the correct location.

A: Yes, the compilation database can be used with other tools besides Clang-Tidy and Clang-Format. The compilation database is a standard format that can be used by any tool that needs to analyze and refactor code.

In this article, we answered some frequently asked questions related to generating compilation databases using qmake. By following the steps outlined in our previous article and using the information provided in this article, you can effectively use qmake to generate a compilation database for your Qt project.

For more information on using qmake and generating compilation databases, refer to the following resources:

By following the steps outlined in this article and exploring the additional resources provided, you can effectively use qmake to generate a compilation database for your Qt project.