TSPI_lineReleaseUserUserInfo function (tspi.h)
The TSPI_lineReleaseUserUserInfo function informs the service provider that the user-user information contained in the LINECALLINFO structure has been processed, and that subsequently received user-user information can now be written into that structure. The service provider sends a LINE_CALLINFO message indicating LINECALLINFOSTATE_USERUSERINFO when new information is available.
LONG TSPIAPI TSPI_lineReleaseUserUserInfo( DRV_REQUESTID dwRequestID, HDRVCALL hdCall );
The identifier of the asynchronous request.
The service provider's handle to the call for which user-user information is to be released. The call state of hdCall can be any.
Returns dwRequestID, or an error number if an error occurs. The lResult actual parameter of the corresponding ASYNC_COMPLETION is zero if the function succeeds, or an error number if an error occurs. Possible return values are as follows:
LINEERR_INVALCALLHANDLE, LINEERR_OPERATIONFAILED, LINEERR_NOMEM, LINEERR_RESOURCEUNAVAIL.
The TSPI_lineReleaseUserUserInfo function permits control of the flow of incoming user-user information on an ISDN connection. When a new, complete user-user information message is received, the service provider informs TAPI using a LINE_CALLINFO message (specifying LINECALLINFOSTATE_USERUSERINFO). The user-user information and other fields in LINECALLINFO can be examined by multiple calls to TSPI_lineGetCallInfo. The service provider must not overwrite previous user-user information in LINECALLINFO with newer information until after TSPI_lineReleaseUserUserInfo has been called. The service provider must buffer subsequently received user-user information until the previous information is released. Any remaining buffered information can be discarded when TSPI_lineCloseCall is invoked.
If this function is invoked while there is no user-user information in LINECALLINFO, the service provider should nevertheless return an indication of success.
For backward compatibility, TAPI automatically returns LINEERR_OPERATIONUNAVAIL if this function is invoked for a call on a line under the control of a service provider that does not export the function.