Is there documentation about the UE4 architecture?

I want to program with the Source code.Is there any documentation about that ? Is it the only way to program by reading the source code?

Hello, joly-zjl

Please note that there is Unreal Engine 4 documentation, which is available online.
To use it, please go to Unreal Engine 5.1 Documentation | Unreal Engine 5.1 Documentation

There, you can find a lot of helpful information about Unreal Engine 4. In particular, you can discover functions and variables of a particular class, its parent and derived classes.

Nevertheless, sometimes you may want to look through source code for deeper understanding. A good practice is to look through header files at first, since some useful information can be found there as well.

Hope this helped!

Good luck!

I konw the UE4 documentation.I am reading the source code and want to find more detail documentation.In the source code,there are some function and macro without comments . I just want to understand that more quickly.
Thanks for your help.