Some make questions for C++ files

These questions are related to make when working with C++ files.

• What is the difference between CPPFLAGS and CXXFLAGS ? What are some common values for these variables ?
  
• In this a partial answer ?
• LDLIBS and LOADLIBES ?
  

By the way to check the default variables that make uses, do the following:

make -p -f /dev/null

While looking for some answers to these questions I found this very helpful anchor.