Creating MEL Projects

Setting Up your Project Directory and CMakeLists.txt

Now you have the MEL library built and installed, it's time to create your own project which uses it. Here's a typical C++ folder structure and CMakeLists.txt you can start with:

Note: You can save yourself some time by downloading the provided project template.

MyProject             # top level of your project
├── CMakeLists.txt    # your top-level CMakeLists.txt
├── build             # conventionally where building occurs
├── include           # where your header files live
    ├── MyClass.hpp   # a class header file
    ├── ...           # more header files
├── src               # where your source files live
    ├── MyClass.cpp   # a class source file
    ├── ...           # more source files
    ├── my_app.cpp    # an application file defining main()

CMakeLists.txt would then look like this:

# set minimum needed CMake version (always required)
cmake_minimum_required(VERSION 3.13)
# create your C++ project
project(MyProject VERSION 0.1.0 LANGUAGES CXX)
# find MEL::MEL and all available MEL::xxx modules
find_package(MEL REQUIRED)
# add your include directories
include_directories("include")
# create an app from your source files
add_executable(my_app "include/MyClass.hpp" "src/MyClass.cpp" "src/my_app.cpp")
# link your app to MEL libraries
target_link_libraries(my_app MEL::MEL)

If your're using MEL classes which target particular hardware, you need to link the the sub-module library that includes them. For example, to use Quanser devices:

target_link_libraries(my_app MEL::quanser)

or to use myRIO:

target_link_libraries(my_app MEL::myrio)

Note that we don't need to link to the core library MEL::MEL because MEL::quanser and MEL::myrio automatically import it as a dependency. You can also link against two compatible MEL sub-module libraries at once:

target_link_libraries(my_app MEL::quanser MEL::myo)

Building your Project

To generate your project build files, open a command prompt at the top level of your project directory and run:

> mkdir build                      # make build directory if it doesn't exist
> cd build                         # change directory to ./build
> cmake .. -G "GENERATOR STRING"   # call cmake with same generator used for MEL

Note: If you are compiling for NI embedded systems (myRIO/cRIO), don't forget to set CMAKE_TOOLCHAIN_FILE when calling CMake on your project. (e.g. -DCMAKE_TOOLCHAIN_FILE="../cmake/nilrt-arm-toolchain.cmake")

Now you can proceed to compile your project:

> cmake --build . --config Release

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