phoneGetDevCaps function (tapi.h)

Article
08/23/2022

The phoneGetDevCaps function queries a specified phone device to determine its telephony capabilities.

Syntax

LONG phoneGetDevCaps(
  HPHONEAPP   hPhoneApp,
  DWORD       dwDeviceID,
  DWORD       dwAPIVersion,
  DWORD       dwExtVersion,
  LPPHONECAPS lpPhoneCaps
);

Parameters

hPhoneApp

Handle to the application's registration with TAPI.

dwDeviceID

Identifier of the phone device to be queried.

dwAPIVersion

Version number of the Telephony API to be used. The high-order word contains the major version number; the low-order word contains the minor version number. This number is obtained with the function phoneNegotiateAPIVersion.

dwExtVersion

Version number of the service provider-specific extensions to be used. This number is obtained with the function phoneNegotiateExtVersion. It can be left zero if no device-specific extensions are to be used. Otherwise, the high-order word contains the major version number; the low-order word contains the minor version number.

lpPhoneCaps

Pointer to a variably sized structure of type PHONECAPS. Upon successful completion of the request, this structure is filled with phone device capabilities information.

Return value

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

PHONEERR_INVALAPPHANDLE, PHONEERR_INVALPOINTER, PHONEERR_BADDEVICEID, PHONEERR_OPERATIONFAILED, PHONEERR_INCOMPATIBLEAPIVERSION, PHONEERR_OPERATIONUNAVAIL, PHONEERR_INCOMPATIBLEEXTVERSION, PHONEERR_NOMEM, PHONEERR_STRUCTURETOOSMALL, PHONEERR_RESOURCEUNAVAIL, PHONEERR_NODRIVER, PHONEERR_UNINITIALIZED, PHONEERR_NODEVICE.

Remarks

Before using phoneGetDevCaps, the application must negotiate the TAPI version number to use (see phoneNegotiateAPIVersion) and, optionally, the extension version to use (see phoneNegotiateExtVersion).

TAPI and extension version numbers are those under which TAPI, Telephony DLL, and service provider must operate. If version ranges do not overlap, the application and API or service-provider versions are incompatible and an error is returned.

Requirements

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