The TSPI_phoneGetExtensionID function retrieves the extension identifier that the service provider supports for the indicated phone device.
LONG TSPI_phoneGetExtensionID(
DWORD dwDeviceID,
DWORD dwTSPIVersion,
LPPHONEEXTENSIONID lpExtensionID
);
Returns zero if the function succeeds, or an error number if an error occurs. Possible return values are as follows:
PHONEERR_INCOMPATIBLEAPIVERSION, PHONEERR_RESOURCEUNAVAIL, PHONEERR_NODRIVER, PHONEERR_OPERATIONFAILED, PHONEERR_NOMEM, PHONEERR_OPERATIONUNAVAIL.
This function is typically called by TAPI in response to an application calling the phoneNegotiateAPIVersion function. The result returned by the service provider should be appropriate for use in a subsequent call to TSPI_phoneNegotiateExtVersion.
PHONEEXTENSIONID, TSPI_phoneNegotiateExtVersion, TSPI_phoneNegotiateTSPIVersion