Sometimes GetActiveObject does not work...

[oransen]

When starting up sometimes GetActiveObject does not get hold of an already running Inventor.

I'm testing a program which uses a part which the program assumes is already loaded, but since GetActiveObject fails the whole program fails.

What could make GetActiveObject fail if a session is already open?

    CLSID InvAppClsid; 
    HRESULT hRes = CLSIDFromProgID (L"Inventor.Application", &InvAppClsid);
    if (FAILED(hRes)) {
        pInvApp = nullptr ;
        return ReturnAndShowCOMError (hRes,L"ConnectToInventor,CLSIDFromProgID failed") ;
    }

    // See if Inventor is already running...
    CComPtr<IUnknown> pInvAppUnk = nullptr ;
    hRes = ::GetActiveObject (InvAppClsid, NULL, &pInvAppUnk);
    if (FAILED (hRes)) {
        // ERROR: Inventor IS running but GetActiveObject fails
        // What can I do to investigate this error?

The COM error code is 0X800401E3.

The meaning is "operation not available" (translated from Italian).

[ekinsb]

It's difficult to say what the problem is.  Connecting to Inventor's API using GetActiveObject is all Microsoft functionality.  Are you running on any kind of "special" system?  For example, is it a server?  I've seen some strange behavior before with that.

[oransen]

I've investigated further and it seems to be a (known) (Microsoft) problem with the ROT (Running Objects Table). If I get any further with this I'll report back here.