CA_DiscardObjHandle
HRESULT CA_DiscardObjHandle (CAObjHandle objectHandle);
Purpose
Use CA_DiscardObjHandle when you no longer need to reference an ActiveX server object. CA_DiscardObjHandle releases resources associated with the object and calls the Release method of the ActiveX server object.
If objHandle is the only reference to the ActiveX server and the ActiveX server is an application, the server application might shut down after you call CA_DiscardObjHandle. If you implement the ActiveX server as a DLL, you must call the Windows SDK function CoFreeUnusedLibraries to unload the DLL. If you do not call CoFreeUnusedLibraries, the DLL does not unload until you exit your program.
Parameters
| Input | ||
| Name | Type | Description |
| objectHandle | CAObjHandle | ActiveX object handle returned by one of the object creation functions in this library or by an ActiveX server method. In an instrument driver generated by the ActiveX Controller Wizard, this includes the New, Open, and Active functions, and other functions that return an object handle. |
Return Value
| Name | Type | Description |
| status | HRESULT | A value indicating whether an error occurred. Negative error codes indicate function failure. Error codes are defined in CVIversion\include\cviauto.h and <Program Files>\National Instruments\Shared\MSDTRedistributables\SDKHeaderFiles\8.1\winerror.h. The LabWindows/CVI ActiveX Library explicitly returns error codes. Other error codes in winerror.h are generated by ActiveX servers and passed on to you by the LabWindows/CVI ActiveX Library. You can use CA_GetAutomationErrorString to get the description of an error code or CA_DisplayErrorInfo to display the description of the error code. |
Additional Information
Library: ActiveX Library
Include file: cviauto.h
LabWindows/CVI compatibility: LabWindows/CVI 5.0 and later
Examples
Refer to the following examples that use the CA_DiscardObjHandle function:
- userint\activex\3DGraph.cws
Open example - userint\activex\3DGraphAxis.cws
Open example - userint\activex\3DGraphColorMap.cws
Open example - userint\activex\3DGraphContours.cws
Open example