the easiest way to manage JSON objects with Qt

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If you are a Gnu/Linux user I strongly recommend to install QJson using your package manager. QJson packages are available for all the major distributions.

OSX users can install QJson using mac ports or homebrew.

QJson source code can be downloaded from its Github page.


QJson requires:

  • Qt 4.0 or greater
  • cmake 2.6 or greater

Some possible cmake options:

  • -DCMAKE_BUILD_TYPE=DEBUG: enables some debug output (other than making easier to debug the code)
  • -DQJSON_BUILD_TESTS=yes or -DKDE4_BUILD_TESTS=yes: builds the unit tests
  • -DCMAKE_INSTALL_PREFIX=${HOME}/testinstall: install qjson in a custom directory
  • -DCMAKE_INCLUDE_PATH=${HOME}/testinstall/include: include a custom include directory
  • -DCMAKE_LIBRARY_PATH=${HOME}/testinstall/lib: include a custom library directory
  • -DLIB_DESTINATION=lib64: if you have a 64 bit system with separate libraries for 64 bit libraries
  • -DQJSON_VERBOSE_DEBUG_OUTPUT:BOOL=ON: more debugging statements are generated by the parser. It’s useful only if you are trying to fix the bison grammar.


For Unix/Linux/Mac:

mkdir build
cd build
cmake -DCMAKE_INSTALL_PREFIX=_preferred_path_ ..
make install
/sbin/ldconfig #if necessary


Note well: these instructions can be outdated, I do not have a Windows machine and I’m not really into Windows development.

Patches and documentation related to Windows are welcome.

This guide assumes you are using MinGW.

The CLI way

After having installed both Qt and cmake add the following line at the end of qtenv.bat (it can be found under C:\Qt\qt_version\bin):

set PATH=%PATH%;C:\path_to_cmake_\bin

Open the “Qt Command Prompt”, go to the directory containing QJson’s sources and do:

mkdir build
cd build
cmake -G "MinGW Makefiles" ..
mingw32-make install

Now you will find libqjson.dll under the build\lib directory.

The GUI way

The Qt Creator IDE can handle cmake-based projects.

In addition to the Qt Windows SDK you have to download and install the Qt Creator IDE.

Then follow these steps:

  1. Start Qt Creator.
  2. Select: File → Open file or project.
  3. Go to the directory containing QJson’s sources.
  4. Open the CMakeLists.txt file.
  5. Open the Projects tab and ensure the build directory points to the path where qjson source code is located.
  6. Select: Build → Build all.

At the end of the build you will find the .dll file under the lib folder.


Let’s face the truth: Symbian is a dead platform. I know someone succeeded in building QJson on Symbian, but he never provided a detailed guide.

I have no experience with Symbian, hence I cannot offer help/support.

As usual patches and documentation are welcome.


Sometimes ago I created a bunch of .pro files that allowed to build QJson using qmake. This revealed to be a poor choice, since I had to support two build systems.

Moreover these .pro files were being used only by Windows developers who didn’t want to install cmake.

These .pro files have been removed from git with commit 66d10c44dd3b21. You can always retrieve them from git history if you miss them; just keep in mind I won’t provide support.