Question

Sample.h

namespace Testing
{
    enum Type
    {
        DATA = 0,
        MORE_DATA
    };
}

Now in Sample2.h, using the same namespace, can I access the DataType defined in Sample.h, without including it?

namespace Testing
{
    Type test;
}

The question has come up, because I have files that implement this, and seem to build with no problem.
Another user is trying to build, but reports that he has to #include “Sample.h” in Sample2.h in order to build.

Answer 1

Yes, you will need to include Sample.h within Sample2.h. The definition of Type is not visible to the compiler within Sample2.h simply because the namespace name is the same within the 2 files.

The only thing you gain by having the same namespace names in the 2 files is that Type does not need to have its namespace stated explicitly in Sample2.h. For instance, if the 2 namespaces were not the same:

Sample.h

namespace Testing
{
    enum Type
    {
        DATA = 0,
        MORE_DATA
    };
}

Sample2.h

#include "Sample.h"

namespace Testing1
{
    Testing::Type test;
}