C++ implementation should be namespaced

[jbayardo]

If you use CRoaring as it comes in the library, it generates a name clash with the Point Cloud Library. This is because of the #include "roaring.h" line in the head of roaring.hh, causing it to bring many functions into the global namespace.

I have "fixed this" by creating

roaring.h

#pragma once

namespace roaring {
#include <roaring/roaring.hh>
}

And including that directly, but it seems like this should be handled library-level.

[lemire]

Yes, that’s a good point.

Do you want to issue a PR?

[AE1020]

I have already patches to get the entirety of roaring to build as C++, which corrects issues like spanning header files with extern "C" { }.

Namespaces similarly should not span headers and only roaring-specific content, so they can go at those locations. So:

 #ifdef __cplusplus
 extern "C" { namespace roaring {
 #endif

I first tried everything under one namespace, which works but it would lead people to saying using namespace roaring; when they want much less.

Then split this up into ::roaring for the C++ exports, ::roaring::api for the C public API vs. ::roaring::internal for service routines.

To the extent anyone knows what namespace best practices are, it tries to follow them by not doing using statements in headers unless it has to for C compatibility.

[lemire]

@AE1020 Could you issue a PR?

[lemire]

This has been fixed.