C++20&Win API プライマリモニターのハンドル取得＆物理モニター情報の列挙

プライマリモニターのハンドルを取得して、その物理モニター情報を列挙するサンプルコードです。

#include <format>
#include <iostream>
#include <string_view>
#include <span>
#include <vector>

#define STRICT
#include <Windows.h>
#include <physicalmonitorenumerationapi.h>
#pragma comment(lib, "dxva2.lib")

inline HMONITOR GetPrimaryMonitorHandle() noexcept
{
    return ::MonitorFromWindow(nullptr, MONITOR_DEFAULTTOPRIMARY);;
}

class PhysicalMonitors final
{
public:
    PhysicalMonitors(HMONITOR monitorHandle)
    {
        DWORD physicalMonitorCount;
        if (!::GetNumberOfPhysicalMonitorsFromHMONITOR(monitorHandle, &physicalMonitorCount))
            return;

        physicalMonitors.resize(physicalMonitorCount);
        if (!::GetPhysicalMonitorsFromHMONITOR(monitorHandle, physicalMonitorCount, physicalMonitors.data()))
            physicalMonitors.clear();
    }

    ~PhysicalMonitors()
    {
        ::DestroyPhysicalMonitors((DWORD)physicalMonitors.size(), physicalMonitors.data());
    }

    auto GetSpan() const noexcept
    {
        return std::span<const PHYSICAL_MONITOR>(physicalMonitors.cbegin(), physicalMonitors.cend());
    }

    HANDLE GetHandleAt(size_t index) const noexcept
    {
        return physicalMonitors[index].hPhysicalMonitor;
    }

    std::wstring_view GetDescriptionAt(size_t index) const noexcept
    {
        return physicalMonitors[index].szPhysicalMonitorDescription;
    }

    DWORD GetCount() const noexcept
    {
        return (DWORD)physicalMonitors.size();
    }

private:
    std::vector<PHYSICAL_MONITOR> physicalMonitors;
};

int main()
{
    std::wcout.imbue(std::locale("Japanese", std::locale::ctype));

    auto primaryMonitorHandle = GetPrimaryMonitorHandle();

    PhysicalMonitors physicalMonitors(primaryMonitorHandle);
    for (auto& physicalMonitor : physicalMonitors.GetSpan())
    {
        std::wcout
            << std::format(L"{:x} - {}",
                (size_t)physicalMonitor.hPhysicalMonitor,
                physicalMonitor.szPhysicalMonitorDescription)
            << std::endl;
    }
}