vk::DynamicLoader without pulling Windows.h everywhere

vk.cpp

#include "vk.hpp"

#include <Windows.h>

namespace vk
{
	DynamicLoader::DynamicLoader() : m_success(false)
	{
#if defined(__linux__)
		m_library = dlopen("libvulkan.so", RTLD_NOW | RTLD_LOCAL);
#elif defined(__APPLE__)
		m_library = dlopen("libvulkan.dylib", RTLD_NOW | RTLD_LOCAL);
#elif defined(_WIN32)
		m_library = LoadLibrary(TEXT("vulkan-1.dll"));
#endif

		m_success = m_library != 0;
		if (!m_success)
		{
			// NOTE there should be an InitializationFailedError, but msvc insists on the symbol does not exist within the scope of this function.
			throw std::runtime_error("Failed to load vulkan library!");
		}
	}

	DynamicLoader::~DynamicLoader() noexcept
	{
		if (m_library)
		{
#if defined(__linux__) || defined(__APPLE__)
			dlclose(m_library);
#elif defined(_WIN32)
			FreeLibrary(m_library);
#endif
		}
	}

	void* DynamicLoader::getProcAddressImpl(const char* function) noexcept
	{
#if defined(__linux__) || defined(__APPLE__)
		return reinterpret_cast<void*>(dlsym(m_library, function));
#elif defined(_WIN32)
		return reinterpret_cast<void*>(GetProcAddress(m_library, function));
#endif
	}

	DispatchLoaderDynamic defaultDispatcherDynamic;
}

vk.hpp

#pragma once

namespace vk
{
	class DynamicLoader
	{
	public:
		DynamicLoader();

		~DynamicLoader() noexcept;

		template <typename T>
		T getProcAddress(const char* function) const noexcept
		{
			return reinterpret_cast<T>(getProcAddressImpl(function));
		}

		bool success() const noexcept { return m_success; }

	private:

		void* getProcAddressImpl(const char* function) noexcept;

	private:
		bool m_success;
	#if defined(__linux__) || defined(__APPLE__)
		void* m_library;
	#elif defined(_WIN32)
		HMODULE m_library;
	#else
	#error unsupported platform
	#endif
	};
}

#define VULKAN_HPP_DEFAULT_DISPATCHER vk::defaultDispatcherDynamic

namespace vk {
	extern DispatchLoaderDynamic defaultDispatcherDynamic;
}

// Kill the default implementation and provide our own, which is a verbatim copy of the provided one,
// but does not expose GetProcAddress in its header (by forcing Windows.h everywhere)
#define VULKAN_HPP_ENABLE_DYNAMIC_LOADER_TOOL 0

#include <vulkan/vulkan.hpp>
#include "vk_mem_alloc.hpp"