TSPI_lineGetExtensionID function (tspi.h)

Article
02/22/2024

The TSPI_lineGetExtensionID function returns the extension identifier that the service provider supports for the indicated line device.

Syntax

LONG TSPIAPI TSPI_lineGetExtensionID(
  DWORD             dwDeviceID,
  DWORD             dwTSPIVersion,
  LPLINEEXTENSIONID lpExtensionID
);

Parameters

dwDeviceID

The line device to be queried.

dwTSPIVersion

An interface version number that was already negotiated for this device using TSPI_lineNegotiateTSPIVersion. This function operates according to the interface specification at this version level.

lpExtensionID

A pointer to a structure of type LINEEXTENSIONID. If the service provider supports provider-specific extensions, it fills this structure with the extension identifier of these extensions. If the service provider does not support extensions, it fills this structure with all zeros. (Therefore, a valid extension identifier cannot consist of all zeros.)

Return value

Returns zero if the function succeeds, or an error number if an error occurs. Possible return values are as follows:

LINEERR_NOMEM, LINEERR_OPERATIONFAILED, LINEERR_OPERATIONUNAVAIL, LINEERR_RESOURCEUNAVAIL.

Remarks

This function is typically called by TAPI in response to an application calling the lineNegotiateAPIVersion function. The result returned by the service provider should be appropriate for use in a subsequent call to TSPI_lineNegotiateExtVersion. An extension identifier of all zeros is not a legal extension identifier, because the all-zeros value is used to indicate that the service provider does not support extensions.

Requirements

Requirement	Value
Target Platform	Windows
Header	tspi.h