What is best practice for C++ Public API?

Question

What is best practice for C++ Public API?

I am working on a C++ project that has multiple namespaces, each with multiple objects. Some objects have the same names, but are in different namespaces. Currently, each object has its own .cpp file and .h file. I am not sure how to word this... Would it be appropriate to create a second .h file to expose only the public API? Should their be a .h file per namespace or per object or some other scope? What might be a best practice for creating Public APIs for C++ libraries?

Thanks For Any Help, Chenz

Answer 1

It is sometimes convenient to have a single class in every .cpp and .h pair of files and to have the namespace hierarchy as the directory hierarchy.
For instance if you have this class:

namespace stuff {
  namespace important {
    class SecretPassword 
    {
       ...
    };
  }
}

then it will be in two files:

/stuff/important/SecretPassword.cpp
/stuff/important/SecretPassword.h

another possible layout might be:

/src/stuff/important/SecretPassword.cpp
/include/stuff/important/SecretPassword.h

Answer 2

G'day,

One suggestion is to take a look at the C++ idiom of Handle-Body, sometimes known as Cheshire Cat. Here's James Coplien's original paper containing the idiom.

This is a well known method for decoupling public API's from implementations.

HTH