The general (non module specific) public interfaces are exported in the library /usr/lib/libradclient.so and defined in the headers
/usr/include/rad/radclient.h – The client function and datatype definitions.
/usr/include/rad/radclient_basetypes.h – Helper routines for managing the built-in rad types.
The examples shown below are just snippets of C code, but at the top of each example for clarity, there is a list of #include statements showing the headers needed for that specific functionality.