HRESULT WFPCancelAsyncRequest( hService, RequestID )
Cancels the specified (or every) asynchronous request being performed on the specified service provider, before its (their) completion.
Parameters HSERVICE hService
Handle to the service provider.
REQUESTID RequestID
The request identifier (NULL to cancel all requests for the specified hService).
Mode Immediate. Although the cancellation process itself is asynchronous, the completion message(s) are associated with the original request, not the cancel request (even if they indicate a WFS_ERR_CANCELED status).
Comments If the RequestID parameter is set to NULL, the command will cancel all asynchronous requests on the specified service that are in progress on behalf of the calling application.
A previously initiated asynchronous request is canceled prior to completion by issuing the WFSCancelAsyncRequest function, specifying the request identifier returned by the asynchronous function. This function is immediate with respect to its calling application, but the cancellation process is inherently asynchronous. On completion, the specified request (or all the requests) will have finished, with a completion message indicating a status of WFS_ERR_CANCELED, unless the cancel request was made after the request had completed.
The cancellation applies to the service provider level. The request is passed through the SPI, and the service provider normally then also cancels any physical I/O or other device operation in progress, in the appropriate manner for the device or service.
Error Codes If the function return is not WFS_SUCCESS, it is one of the following error conditions: