HOWTO: How to Enumerate Monitors in Win 98 and Windows 2000

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This article was previously published under Q197671

SUMMARY

Starting with Microsoft Windows 98 and Microsoft Windows 2000, multiple monitors could be attached to a computer and connected to the desktop. This article contains sample code showing how to enumerate those devices attached to the desktop.

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MORE INFORMATION

The following code is for a small console-mode application that enumerates the attached display devices:

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Sample Code

   #include <windows.h>
   #include <stdio.h>
   #ifndef SM_CMONITORS

       typedef HANDLE HMONITOR;

   #endif
   #ifndef DISPLAY_DEVICE_PRIMARY_DEVICE

       typedef struct _DISPLAY_DEVICE {
        DWORD  cb;
        TCHAR  DeviceName[32];
        TCHAR  DeviceString[128];
        DWORD  StateFlags;
       } DISPLAY_DEVICE, *PDISPLAY_DEVICE, *LPDISPLAY_DEVICE;
       #define DISPLAY_DEVICE_ATTACHED_TO_DESKTOP 0x00000001
       #define DISPLAY_DEVICE_MULTI_DRIVER        0x00000002
       #define DISPLAY_DEVICE_PRIMARY_DEVICE      0x00000004
       #define DISPLAY_DEVICE_VGA             0x00000010

   #endif

   main (int argc, char**argv)
   {

    int i;
   int j=0;
    BOOL (WINAPI* pEnumDisplayDevices)(PVOID,DWORD,PVOID,DWORD);

    (FARPROC)pEnumDisplayDevices = GetProcAddress(
        LoadLibrary("USER32"), "EnumDisplayDevicesA");

    if (pEnumDisplayDevices)
    {
        DISPLAY_DEVICE dd;
        ZeroMemory(&dd, sizeof(dd));
        dd.cb = sizeof(dd);

        printf("*** EnumDisplayDevices\n");

        for (i=0; (*pEnumDisplayDevices)(NULL, i, &dd, 0); i++)
        {
         j++;
            printf("    DeviceName:   '%s'\n", dd.DeviceName);
            printf("    DeviceString: '%s'\n", dd.DeviceString);
            printf("    Flags:        %08X %s%s\n",
                dd.StateFlags,
                ((dd.StateFlags & DISPLAY_DEVICE_ATTACHED_TO_DESKTOP) ?
"Desktop " : ""),

                ((dd.StateFlags & DISPLAY_DEVICE_PRIMARY_DEVICE) ? "Primary

" : ""));

           }
       }

   return j;
   }

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