Base for C++ API #cpp

FooAPI.h

#include "FooAPIDefs.h"

#define FOOINTERFACES_VERSION 7

extern "C" FOOINTERFACES_API IFooFactory* GetFooFactoryPtr(const uchar* options = nullptr, uint32_t version = FOOINTERFACES_VERSION) noexcept;

// API entry point
inline IFooFactory::Ptr GetFooFactory(const uchar* options = nullptr, uint32_t version = FOOINTERFACES_VERSION) {
  return IFooFactory::Ptr(GetFooFactoryPtr(options, version));
}

FooAPIDefs.h

#ifdef _WIN32
#    ifdef FOOINTERFACES_EXPORTS
#        define FOOINTERFACES_API __declspec(dllexport)
#    else
#        define FOOINTERFACES_API __declspec(dllimport)
#    endif
#else
#    define FOOINTERFACES_API
#endif

fooImpl.cpp

namespace FooImplementation
{
	extern "C" FOOINTERFACES_API IFooFactory* GetFooFactoryPtr(const uchar* options, uint32_t version) noexcept
	{
		assert(options != nullptr);
		assert(version == FOOINTERFACES_VERSION);

		IFooFactory* outPtr = nullptr;
		try
		{
			if (version == FOOINTERFACES_VERSION)
			{
				outPtr = new SomeFooFactoryImplementation(options);
			}
		}
		catch (...)
		{
			assert(false && "Failed to create factory object");
		}

		return outPtr;
	}
}