Writing an example module for event-driven

You are ready to write your own code that uses the tools in the event-driven library to process events. An example module is provided in example_module that you can use as the basis for writing a module that can be integrated into the YARP framework.

The module has the following functionality:

• Reading a *.ini file to load configuration options, and setting options via command line arguments.
• Clean exit by capturing ctrl+c commands and allowing functions to close ports and clean memory.
• Example event-driven ports for reading and writing events.
• A synchronous thread, typically used to show a visualisation or status/debug messages at a readable rate.
• An asynchronous thread, used to read events at sub-millisecond rates and perform processing as required.
• An example CMake file for installing the generated binaries in the install location of event-driven, as well as installation of the configuration and application files in locations required by YARP.

How to use the example-module

First, copy the example files to the new location of your project, e.g. the same folder where you have cloned event-driven. Assuming a<path_to_projects> directory:

cp -r <path_to_projects>/event-driven/documentation/example-module <path_to_projects>

The project can be compiled with modifications:

cd <path_to_projects>/example-module
mkdir build && cd build
cmake .. -DCMAKE_INSTALL_PREFIX=$INSTALL_DIR
make install -j4

However, some modifications should be made to personalise the project. The first step would be to change the folder, file and project name:

cd <path_to_projects>
mv example-module <my-module-name>
mv <my-module-name>/example-module.cpp <my-module-name>/<my-module-name>.cpp
mv example-module.ini <my-module-name>.ini
mv app_example-module.xml app_<my-module-name>.xml
nano <my-module-name> CMakeLists.txt

On line 5 change the project name to <my-module-name>, then save (ctrl+o) and exit (ctrl+x).

nano <my-module-name>/<my-module-name>.cpp

On line 7, 19,24, and 124 change the class, constructor and declaration to <my-module-name>, then save (ctrl+o) and exit (ctrl+x).

Change the first line of the default configuration file and the lines that refer to example-module in the example yarpmanager application. For example:

nano <my-module-name>/<my-module-name>.ini
nano <my-module-name>/app_<my-module-name>.xml

or if you like:

sed -i 's/example-module/<my-module-name>/g' <my-module-name>.xml

The module should now be personalised to your processing task.

If you like, you can import the project into your favourite IDE. To do so, e.g. for QtCreator open a new project by selecting <path_to_projects>/<my-module-name>/CmakeLists.txt. Select the kits release and debug modifying the build directory to <path_to_projects>/<my-module-name>/build and <path_to_projects>/<my-module-name>/build-debug respectively. You should now be able to edit, compile, run and debug the module from within QtCreator.