CA_VariantGetIUnknownPtr
HRESULT CA_VariantGetIUnknownPtr (const VARIANT *variant, LPUNKNOWN **value);
Purpose
Copies the value in a variant into a variable that is a pointer to the LPUNKNOWN type. An LPUNKNOWN value is a pointer to an unknown interface.
CA_VariantGetIUnknownPtr returns an error if the variant does not contain a pointer to an LPUNKNOWN value.
Parameters
| Input | ||
| Name | Type | Description |
| variant | const VARIANT * | Pointer to a variant that contains an LPUNKNOWN pointer. |
| Output | ||
| Name | Type | Description |
| value | LPUNKNOWN * | LPUNKNOWN pointer that CA_VariantGetIUnknownPtr copies from the variant. |
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