Question about clang documentation or better a book

Hi everyone,

i'm new to clang and i need to parse C++ code that can use custom c++
functions/variables i write myself and then i need a way to create my
own AST that has access to the own defined functions/variables.

I was not able to find a book about clang and my llvm book talks to less
about clang. Can someone point me in the right direction ?

best regards,

Steven Truppe