pyqgis - Understanding QGIS API documentation

Is there an introduction or guidelines how to read the QGIS API documentation?

For example, I want to write a vector layer. A quick search brings me to the API documentation page of QgsVectorFileWriter.

This is a very long page with an inheritence diagram, different classes, public classes, public membership functions,... but I don't fully understand what this means.

I can figure out that I need the QgsVectorFileWriter::QgsVectorFileWriter function, but also in this part I have some questions:

• here are three identical(?) functions listed?


• which variables are mandatory and which are optional?

I've found some useful resources on pyqgis at:

but afaik these resources don't give a gentle introduction on how to read the API docs.

I think understanding how to read the API documentation would really help me to write my own code rather than searching for examples.