CA_ServerQueryInterface
- Updated2023-02-21
- 2 minute(s) read
CA_ServerQueryInterface
HRESULT CA_ServerQueryInterface (IUnknown *thisInterfacePtr, const IID *interfaceId, void *newInterfacePtr);
Purpose
Implementation of the IUnknown::QueryInterface method used in the ActiveX servers generated by the ActiveX Server Wizard. This function queries a COM object as to whether it implements a specific interface.
Parameters
| Input | ||
| Name | Type | Description |
| thisInterfacePtr | IUnknown * | The IUnknown interface pointer of your ActiveX object. |
| interfaceId | const IID * | Interface id for the interface requested from the object. |
| Output | ||
| Name | Type | Description |
| newInterfacePtr | void * | The interface pointer (of the type passed in the Interface Id
parameter) obtained from your ActiveX object. Pass the address of an interface pointer variable of the required interface type. |
Return Value
| Name | Type | Description | ||
| status | HRESULT | A value indicating whether an error occurred. Function failure is indicated by a negative error code. 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 the COM runtime and passed on to you by the 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.
The error codes defined in <Program Files>\National Instruments\Shared\MSDTRedistributables\SDKHeaderFiles\8.1\winerror.h are too numerous to display here. These error codes can be returned to your ActiveX clients. |
Additional Information
Library: ActiveX Library
Include file: cviauto.h
LabWindows/CVI compatibility: LabWindows/CVI 6.0 and later