Why does COM Initialization Fail?

[Simon White]

Hi

I wrote a Powerbasic program to use a COM object written in Visual FoxPro. The COM object is an "exe" and it works with other environments but fails in PowerBasic. I assume I have configured something wrong in PowerBasic. Can anyone see what I have done wrong. I have tried this two ways; one using PowerBasic's Let command and secondly with the WinAPI and both fail.

Thanks,
Simon

' Version Dependent ProgIDs
$PROGID_dcvfpsrvc_dcvfpsrvcdCVFPSrvc = "dcvfpsrvc.dCVFPSrvc"

' Version Independent ProgIDs
$PROGID_dcvfpsrvc_dcvfpsrvc = "dcvfpsrvc.dCVFPSrvc"

' Class Identifiers
$CLSID_dcvfpsrvc_dcvfpsrvc = GUID$("{E3238B33-AC18-42FD-BFDF-97AD0973754B}")

' Interface Identifiers
$IID_dcvfpsrvc_Idcvfpsrvc = GUID$("{9E0C18A3-B124-49E3-A286-A5A2709A08BE}")

' Interface Name  : Idcvfpsrvc
' Description     : dcvfpsrvc.dCVFPSrvc
' Class Name      : dcvfpsrvc
' ClassID         : $CLSID_dcvfpsrvc_dcvfpsrvc
' ProgID          : $PROGID_dcvfpsrvc_dcvfpsrvc
' Version ProgID  : $PROGID_dcvfpsrvc_dcvfpsrvcdCVFPSrvc
INTERFACE Idcvfpsrvc $IID_dcvfpsrvc_Idcvfpsrvc
    INHERIT IDISPATCH

    METHOD destroyworkers <0> () AS VARIANT
    METHOD execute <1> () AS VARIANT
    METHOD GetWorker <2> () AS VARIANT
    METHOD ProcessQueue <3> () AS VARIANT
    METHOD startworkers <4> () AS VARIANT
    METHOD stopworkers <5> () AS VARIANT
    METHOD writetolog <6> () AS VARIANT
END INTERFACE    
Local loVFP AS Idcvfpsrvc  
  IF CoInitializeEx(BYVAL %NULL, %COINIT_APARTMENTTHREADED) = %S_OK THEN

      IF CoCreateInstance($CLSID_dcvfpsrvc_dcvfpsrvc, BYVAL %NULL, %CLSCTX_LOCAL_SERVER,$IID_dcvfpsrvc_Idcvfpsrvc,loVFP) = %S_OK  THEN


'   LET loVFP = NEWCOM CLSID CLSID$("dcvfpsrvc.dCVFPSrvc") 'LIB "C:\Business\dCipherComputing\Applications\dCVFPSrvc\VFP9\dcvfpsrvc.exe"
...

[José Roca]

Because you're using it wrongly.

Instead of

Local loVFP AS Idcvfpsrvc  
  IF CoInitializeEx(BYVAL %NULL, %COINIT_APARTMENTTHREADED) = %S_OK THEN

      IF CoCreateInstance($CLSID_dcvfpsrvc_dcvfpsrvc, BYVAL %NULL, %CLSCTX_LOCAL_SERVER,$IID_dcvfpsrvc_Idcvfpsrvc,loVFP) = %S_OK  THEN


'   LET loVFP = NEWCOM CLSID CLSID$("dcvfpsrvc.dCVFPSrvc") 'LIB "C:\Business\dCipherComputing\Applications\dCVFPSrvc\VFP9\dcvfpsrvc.exe"
...

use

Local loVFP AS Idcvfpsrvc  
loVFP = NEWCOM $PROGID_dcvfpsrvc_dcvfpsrvcdCVFPSrvc
...

[Simon White]

HI

I tried your code and it still does not work. In fact sometimes PowerBasic just stops working when I try it in debug mode.

Simon

[Dominic Mitchell]

Is that Visual FoxPro COM object something I can download and try?

[Simon White]

Thank-you for your offer but I now have the COM object working correctly. My next problem is how to correctly build a Windows NT Service in PowerBasic that will use the VFP COM Object.

I built a similar service in PureBasic but I am having difficulty getting the service to run in PowerBasic.

PowerBasic installs the service and deletes the service but it will not start the service. When I try to start the service I get the first error ERROR_FAILED_SERVICE_CONTROLLER_CONNECT

Simon

SUB Service_Start(tcService AS STRINGZ)
   LOCAL lnErr AS LONG
   DIM ServiceTable(0 TO 1) AS LOCAL SERVICE_TABLE_ENTRY

   WriteToLog("Service_Start() > Start")
   ServiceTable(0).lpServiceName = VARPTR(tcService)
   ServiceTable(0).lpServiceProc = CODEPTR(Service_MainLoop)
   ServiceTable(1).lpServiceName = %NULL
   ServiceTable(1).lpServiceProc = %NULL

   IF StartServiceCtrlDispatcher(BYVAL VARPTR(ServiceTable(0))) = 0 THEN
      lnErr=GetLastError()
      SELECT CASE lnErr
         CASE %ERROR_FAILED_SERVICE_CONTROLLER_CONNECT
            WriteToLog("Last Error FAILED_SERVICE_CONTROLLER_CONNECT")
         CASE %ERROR_INVALID_DATA
            WriteToLog("Last Error INVALID_DATA")
         CASE %ERROR_SERVICE_ALREADY_RUNNING
            WriteToLog("Last Error SERVICE ALREADY_RUNNING")
         CASE ELSE
            WriteToLog("Last Error "+FORMAT$(lnErr,"##########"))
      END SELECT
   END IF
   WriteToLog("Service_Start() > End")
END SUB