I want to work with QGIS 3.4 in a C++ Qt project, but the API in version 3 has been completely changed and the sample code for older version don't compile anymore. Is there some sample code which shows the best way of using new API or some documents or tutorials which show me the ropes of using new API?
I just took a look in changelogs and the official documents but none of them were what they really can be helpful for me.