CA_ServerDllGetClassObject
HRESULT CA_ServerDllGetClassObject (HINSTANCE serverHInstance, const CLSID *classId, const IID *interfaceId, void *interfacePtr);
Purpose
Implementation of the DllGetClassObject function used in the DLL ActiveX servers generated by the ActiveX Server Wizard. The COM runtime uses this function to create a class factory object. The class factory object is used to create COM objects. The COM runtime is the part of the operating system that provides COM services and performs COM-related tasks.
Parameters
| Input | ||
| Name | Type | Description |
| serverHInstance | HINSTANCE | The HINSTANCE of your server. Note that the HINSTANCE is passed in as an argument to DllMain and WinMain. If your code uses main instead of WinMain as the module entry point, this value is not available. Therefore, EXE servers must use WinMain as their entry point. |
| classId | const CLSID * | Class id of the class whose class object is requested. |
| interfaceId | const IID * | Interface id of the class object that is requested. Usually this value is IID_IClassFactory. |
| Output | ||
| Name | Type | Description |
| interfacePtr | void * | The interface pointer obtained from the class object (of the type passed in the interfaceId parameter). 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