Win32EnumDisplayDevices.cpp

#include <cstdio>
#include <Windows.h>

static void PrintDisplayDeviceStateFlags(DWORD flags)
{
    if (flags & DISPLAY_DEVICE_ATTACHED_TO_DESKTOP)
        printf("    ATTACHED_TO_DESKTOP\n");

    if (flags & DISPLAY_DEVICE_MULTI_DRIVER)
        printf("    MULTI_DRIVER\n");

    if (flags & DISPLAY_DEVICE_PRIMARY_DEVICE)
        printf("    PRIMARY_DEVICE\n");

    if (flags & DISPLAY_DEVICE_MIRRORING_DRIVER)
        printf("    MIRRORING_DRIVER\n");

    if (flags & DISPLAY_DEVICE_VGA_COMPATIBLE)
        printf("    VGA_COMPATIBLE\n");
}

static void Win32EnumDisplayDevices()
{
    DWORD displayAdapterIndex = 0;

    while (true) {
        DISPLAY_DEVICE displayAdapter{};
        displayAdapter.cb = sizeof(displayAdapter);

        const auto adapterOk = EnumDisplayDevices(nullptr, displayAdapterIndex, &displayAdapter, EDD_GET_DEVICE_INTERFACE_NAME);
        if (!adapterOk)
            break;

        printf("Display adapter %u:\n", displayAdapterIndex);
        printf("  DeviceName = %ls\n", displayAdapter.DeviceName);
        printf("  DeviceString = %ls\n", displayAdapter.DeviceString);
        printf("  StateFlags = 0x%08x\n", displayAdapter.StateFlags);
        PrintDisplayDeviceStateFlags(displayAdapter.StateFlags);
        printf("  DeviceId = %ls\n", displayAdapter.DeviceID);
        printf("  DeviceKey = %ls\n", displayAdapter.DeviceKey);

        DWORD displayMonitorIndex = 0;

        while (true) {
            {
                DISPLAY_DEVICE displayMonitor{};
                displayMonitor.cb = sizeof(displayMonitor);

                const auto monitorOk = EnumDisplayDevices(displayAdapter.DeviceName, displayMonitorIndex, &displayMonitor, 0);
                if (!monitorOk)
                    break;

                printf("  Display monitor %u:\n", displayMonitorIndex);
                printf("    DeviceName = %ls\n", displayMonitor.DeviceName);
                printf("    DeviceString = %ls\n", displayMonitor.DeviceString);
                printf("    StateFlags = 0x%08x\n", displayMonitor.StateFlags);
                PrintDisplayDeviceStateFlags(displayMonitor.StateFlags);
                printf("    DeviceId = %ls\n", displayMonitor.DeviceID);
                printf("    DeviceKey = %ls\n", displayMonitor.DeviceKey);
            }
            {
                DISPLAY_DEVICE displayMonitor{};
                displayMonitor.cb = sizeof(displayMonitor);

                const auto monitorOk = EnumDisplayDevices(displayAdapter.DeviceName, displayMonitorIndex, &displayMonitor, EDD_GET_DEVICE_INTERFACE_NAME);
                if (!monitorOk)
                    break;

                printf("    DeviceId[DEVICE_INTERFACE_NAME] = %ls\n", displayMonitor.DeviceID);
            }

            displayMonitorIndex++;
        }

        displayAdapterIndex++;
    }
}

int main()
{
    Win32EnumDisplayDevices();

    return 0;
}