Question

In the registry there is one ( or more ) key depending how many monitors you have HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\DISPLAY\DEL404C\{Some Unique ID}\Device Parameters\EDID which is a REG_BINARY key. In my case this is :

00 FF FF FF FF FF FF 00 10 AC 4C 40 53 43 34 42 34 14 01 03 0A 2F 1E 78 EE EE 95 A3 54
4C 99 26 0F 50 54 A5 4B 00 71 4F 81 80 B3 00 01 01 01 01 01 01 01 01 01 01 21 39 90 30 
62 1A 27 40 68 B0 36 00 DA 28 11 00 00 1C 00 00 00 FF 00 34 57 31 4D 44 30 43 53 42 34 
43 53 0A 00 00 00 FC 00 44 45 4C 4C 20 50 32 32 31 30 0A 20 20 00 00 00 FD 00 38 4B 1E 
53 10 00 0A 20 20 20 20 20 20 00 FA

This reg_binary value contains information (such as Serial Number and Type) about the connected monitor. I only need these two values. My question is how can i read these values using C or C++?

I have a VB script which can do this:
‘you can tell If the location contains a serial number If it starts with &H00 00 00 ff
strSerFind=Chr(&H00) & Chr(&H00) & Chr(&H00) & Chr(&HfF)

‘or a model description If it starts with &H00 00 00 fc

strMdlFind=Chr(&H00) & Chr(&H00) & Chr(&H00) & Chr(&Hfc)

This link also contains information about EDID: http://en.wikipedia.org/wiki/Extended_display_identification_data

Could someone help me, how can i do this in C? I can find only VB script examples, but unfortunately i don’t understand them, and also it would be very important for me.

Answer 1

   DWORD GetLocalMachineProfileBuffer(BYTE* pBuffer, DWORD nMaxLength )
    {
        CString szSubKey = "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\DISPLAY\DEL404C{Some Unique ID}\Device Parameters\EDID";

        DWORD   rc; 
        DWORD   dwType; 
        HKEY    hOpenedKey;

        if( ERROR_SUCCESS == RegOpenKeyEx (
                HKEY_LOCAL_MACHINE, // handle of open key 
                szSubKey,               // address of name of subkey to open 
                0,                  // reserved 
                KEY_READ,       // security access mask 
                &hOpenedKey            // address of handle of open key 
                ) )
        {
            rc = RegQueryValueEx( 
                hOpenedKey, 
                (const char*)szValueName, 
                0, 
                &dwType, 
                (LPBYTE)pBuffer, 
                &nMaxLength ); 
            if( rc != ERROR_SUCCESS ) 
            { 
                return (DWORD)-1;
            } 
            else 
            { 
                ASSERT( dwType == REG_BINARY ); 
            } 

            RegCloseKey( hOpenedKey );
            return nMaxLength; 
        }
        else
        {
            return (DWORD)-1;
        }   
    }

call it like this:

BYTE Buffer[20000];
DWORD nLength = GetLocalMachineProfileBuffer( Buffer, sizeof( Buffer ) );