lineGetAppPriorityA function (tapi.h)

The lineGetAppPriority function enables an application to determine whether or not it is in the handoff priority list for a particular media mode or Assisted Telephony request mode and, if so, its position in the priority list.


LONG lineGetAppPriorityA(
  LPCSTR            lpszAppFilename,
  DWORD             dwMediaMode,
  DWORD             dwRequestMode,
  LPVARSTRING       lpExtensionName,
  LPDWORD           lpdwPriority



A pointer to a string that contains the application executable module file name, without directory data. In API version 2.0 or later, the parameter can be in long file name format, of which the 8.3 file name format is a proper subset. Long file names, unlike 8.3 file names, are case preserving. Neither file name format is case sensitive. For more information, see File Name Conventions. In API versions earlier than 2.0, the parameter must specify a file name in the 8.3 format; long file names cannot be used.


A media mode for which the priority data is to be obtained. The value can be one of the LINEMEDIAMODE_ Constants; only a single bit can be on. The value 0 should be used if verifying application priority for Assisted Telephony requests.


A pointer to structure of type LINEEXTENSIONID. This parameter is ignored.


The conditions for this parameter are, if the dwMediaMode parameter is zero, this parameter specifies the Assisted Telephony request mode for which priority is to be checked. It must be LINEREQUESTMODE_MAKECALL. This parameter is ignored if dwMediaMode is non-zero.


This parameter is ignored.


A pointer to a DWORD-size memory location into which TAPI writes the priority of the application for the specified media or request mode. The value 0 is returned if the application is not in the stored priority list and does not currently have any line device open with ownership requested of the specified media mode or having registered for the specified request mode.

In API versions earlier than 2.0, the value –1 (0xFFFFFFFF) is returned if the application has the line open for the specified media mode or has registered for the specified requests, but the application is not in the stored priority list; that is, it is in the temporary priority list only. In API version 2.0 or later, the value 0 is returned to indicate this condition.

Otherwise, the value indicates the application position in the list; 1 being highest priority, and increasing values indicating decreasing priority.

Return value

Returns zero if the request succeeds or a negative error number if an error occurs. Possible return values are:



If LINEERR_INVALMEDIAMODE is returned, the value specified in dwMediaMode is not zero, not a valid extended media mode, and not one of the LINEMEDIAMODE_ Constants, or more than one bit is on in the parameter value.


The tapi.h header defines lineGetAppPriority as an alias which automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see Conventions for Function Prototypes.


Target Platform Windows
Header tapi.h
Library Tapi32.lib
DLL Tapi32.dll

See also


Supplementary Line Service Functions

TAPI 2.2 Reference Overview