Clsid

How do I find out what the CLSID is going to be for my DLL when I register it?

The DLL project name is "eth0" and the DLL class name is "CShellExt". I compiled and registered it, searched the registry for "eth0.CShellExt" and found it under the key "{5BFAC3A1-8B25-44E0-8A38-0FA0980A5355}" so I made the following .reg file

Code:

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REGEDIT4

[HKEY_CLASSES_ROOT\jpegfile\shellex\ContextMenuHandlers\eth0]
@="{5BFAC3A1-8B25-44E0-8A38-0FA0980A5355}"

[HKEY_CLASSES_ROOT\giffile\shellex\ContextMenuHandlers\eth0]
@="{5BFAC3A1-8B25-44E0-8A38-0FA0980A5355}"

[HKEY_CLASSES_ROOT\pngfile\shellex\ContextMenuHandlers\eth0]
@="{5BFAC3A1-8B25-44E0-8A38-0FA0980A5355}"

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But it does not seem to be working. How would I check that I am using the correct CLSID?

What are you using the clsid for?

For adding a context menu to the right click on images.
The non-working setup is on eth0.org, its just a winrar sfx that installs the dll and some exes to c:\windows\eth0\ the dll handels the selected images when you right click on them and select one of my added options, then the dll calls the exe to upload them.

CLSID is a struct: {DWORD, WORD, WORD, BYTE[8]}
for C your CLSID is
const CLSID clsidID = {0x5BFAC3A1, 0x8B25, 0x44E0, {0x8A, 0x38, 0x0F, 0xA0, 0x98, 0x0A, 0x53, 0x55}};

What about for a VB ActiveX DLL?

So no one knows how to find the CLSID that a dll is going to be assigned when its registered?

A dll, ocx,... may have more than one COM object and so more than one CLSID. If you want to find which CLSIDs a library registers you must search the registry. The following code searches for CLSIDs registered by comctl32.ocx.

Code:

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#include <windows.h>
#include <string.h>

void SearchRegistry()
{
        LONG lr = ERROR_SUCCESS;
        HKEY hKey = NULL;
        HKEY hEnumKey = NULL;
        HKEY hIpsKey = NULL;
        DWORD dwIndex = 0;
        char szClsidName[0xff];
        char szDLLName[0xff];
        char szProgID[0xff];
        char * szSearchStr = "C:\\WINDOWS\\SYSTEM32\\COMCTL32.OCX";
        DWORD dwCount = 0xff;
        LONG lcnt = 0;

        lr = RegOpenKeyExA(HKEY_CLASSES_ROOT, "CLSID", 0, KEY_READ, &hKey);
       
        while (lr = RegEnumKeyA(hKey, dwIndex++, szClsidName, dwCount) == ERROR_SUCCESS)
        {
                lr = RegOpenKeyExA(hKey, szClsidName, 0, KEY_READ, &hEnumKey);
                lr = RegOpenKeyExA(hEnumKey, "InprocServer32", 0, KEY_READ, &hIpsKey);
                lr = RegQueryValueA(hIpsKey, NULL, szDLLName, &lcnt);
                if (lr == ERROR_SUCCESS)
                {
                        _strupr(szDLLName);
                        if (strcmp(szSearchStr, szDLLName) == 0)
                        {
                                printf("CLSID: %s\n", szClsidName);
                                RegCloseKey(hIpsKey);
                                lr = RegOpenKeyExA(hEnumKey, "ProgID", 0, KEY_READ, &hIpsKey);
                                lr = RegQueryValueA(hIpsKey, NULL, szProgID, &lcnt);
                                if (lr == ERROR_SUCCESS)
                                        printf("ProgID: %s\n\n", szProgID);
                                else
                                        printf("ProgID: not found\n\n");
                        }
                }
                RegCloseKey(hIpsKey);
                RegCloseKey(hEnumKey);
        }
        RegCloseKey(hKey);
}

int main()
{
        SearchRegistry();
        return 0;
}

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Note that with the above we may not find all the entries for comctl32.ocx since it may be defined with the alternatives "%SystemRoot%\Windows\System32\comctl32.ocx" or "comctl32.ocx" so it would be more appropriate to check the last 12 chars of the string.