# Example (JKQTPlotter): CMake Example  {#JKQTCMakeLinkExample}

This project (see [`cmake_link_example`](https://github.com/jkriege2/JKQtPlotter/tree/master/examples/cmake_link_example) demonstrates how to link against JKQTPlotter using CMake. See http://jkriege2.github.io/JKQtPlotter/page_buildinstructions.html for details on how to build JKQTPlotter with CMake

This example uses very simple code, which simply displays a plotter and shows some data. The important part of this example is the ´CMakeLists.txt`-file:
```
    # set minimum required CMake-Version
    cmake_minimum_required(VERSION 3.0)

    # set Project name
    set(EXAMPLE_NAME simpletest)
    set(EXENAME jkqtptest_${EXAMPLE_NAME})
    project(${EXAMPLE_NAME} LANGUAGES CXX)

    # some basic configurations
    set(CMAKE_AUTOMOC ON)
    set(CMAKE_AUTORCC ON)
    set(CMAKE_AUTOUIC ON)
    set(CMAKE_INCLUDE_CURRENT_DIR ON)
    set(CMAKE_CXX_STANDARD 11)
    set(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS ON)

    # Configure project for usage of Qt5
    find_package(Qt5 5.12 REQUIRED Core Gui Widgets PrintSupport Svg Xml OpenGl)

    # include JKQTPlotter
    find_package(JKQTCommonLib)
    find_package(JKQTMathTextLib)
    find_package(JKQTPlotterLib)

    # For Visual Studio, we need to set some additional compiler options
    if(MSVC)
        add_compile_options(/EHsc)
        # To enable M_PI, M_E,...
        add_definitions(/D_USE_MATH_DEFINES)
        # To Prevent Errors with min() and max()
        add_definitions(/DNOMINMAX)
        # To fix error: C2338: va_start argument must not
        # have reference type and must not be parenthesized
        add_definitions(/D_CRT_NO_VA_START_VALIDATION)
    endif()

    # add the example executable 
    add_executable(${EXENAME} WIN32 simpletest.cpp)
    # ... and link against JKQTPlotterLib 
    #    (you could use JKQTPlotterSharedLib if you don't want to link againast the 
    #     static version, but against the shared/DLL version).
    target_link_libraries(${EXENAME} JKQTPlotterLib)
```

To build this example, you first need to make a subdirectory `build` and then call CMake form that subdirectory:
```.sh
    $ mkdir build
    $ cd build
    $ cmake .. -G "<GENERATOR>" "-DCMAKE_PREFIX_PATH=<path_to_your_qt_sources> -DCMAKE_MODULE_PATH=<path_to_lib/cmake_dir_of_JKQTPLOTTER>"
```
The you can use the generated makefiles (e.g. load them in an editor, or build them jsing `make`). In the last line above, you need to specify two directories:
  - `<path_to_your_qt_sources>` points to you Qt installation
  - `<path_to_lib/cmake_dir_of_JKQTPLOTTER>` points to the directory containing the `XYZ.cmake`-files from the JKQTPlotter build. Typically this is `<JKQTPLOTTER_INSTALL_DIR>/lib/cmake`, where `<JKQTPLOTTER_INSTALL_DIR>` is the directory into which you installed JKQTPlotter.