CA_UnregisterAllEventCallbacks
- Updated2023-02-21
- 1 minute(s) read
HRESULT CA_UnregisterAllEventCallbacks (CAObjHandle serverObject, const IID *eventClassIID);
Purpose
Unregisters all callbacks in a particular event class for an ActiveX server object.
You can register only one callback for each event fired from a particular server object instance. If you want to change the callback functions for all of the events in an event class, you must first use this function to unregister the existing callbacks.
Parameters
| Input | ||
| Name | Type | Description |
| serverObject | CAObjHandle | The CAObjHandle of the server object from which you no longer want to receive events. |
| eventClassIID | const IID * | The IID that identifies the event class of the event callbacks that you want to unregister. |
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 5.5 and later