2.2.4.1.4.3 GetDevCaps

The GetDevCaps packet is transmitted from a TAPI client to a TAPI server in a remote procedure call. Sending this packet queries a specified phone device to determine its telephony capabilities.

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Req_Func
Reserved1
hPhoneApp
dwDeviceID
dwTSPIVersion
dwExtVersion
lpPhoneCaps
Reserved2
Reserved3
Reserved4
Reserved5
Reserved6
Reserved7
Reserved8
Reserved9
VarData (variable)
...

Req_Func (4 bytes): The identifier of the function that will be invoked on the remote server. This value MUST be set to 95.

Return Values

On completion of ClientRequest, this field MUST contain the result of the encapsulated telephony request. A value of 0 indicates success, and a PHONEERR_Constants value indicates failure. The remote server MUST complete this call synchronously.

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

Name	Value
PHONEERR_INVALAPPHANDLE	0x00000008
PHONEERR_INVALPOINTER	0x00000015
PHONEERR_BADDEVICEID	0x00000002
PHONEERR_OPERATIONFAILED	0x0000001C
PHONEERR_INCOMPATIBLEAPIVERSION	0x00000003
PHONEERR_OPERATIONUNAVAIL	0x0000001D
PHONEERR_INCOMPATIBLEEXTVERSION	0x00000004
PHONEERR_NOMEM	0x0000001A
PHONEERR_STRUCTURETOOSMALL	0x00000021
PHONEERR_RESOURCEUNAVAIL	0x0000001F
PHONEERR_NODRIVER	0x00000019
PHONEERR_UNINITIALIZED	0x00000022
PHONEERR_NODEVICE	0x00000018

Reserved1 (4 bytes): An unsigned 32-bit integer. MUST be set to zero when sent and MUST be ignored on receipt.

hPhoneApp (4 bytes): An HPHONEAPP. The handle to the application registration with TAPI. This field MUST have been obtained by sending the Initialize packet.

dwDeviceID (4 bytes): An unsigned 32-bit integer. The identifier of the phone device to be queried. A valid value of dwDeviceID is in the range 0 to dwNumDevs – 1. The client obtains dwNumDevs by sending a Initialize packet to the remote server.

dwTSPIVersion (4 bytes): An unsigned 32-bit integer. The version number of the TAPI 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 by using NegotiateAPIVersion.

dwExtVersion (4 bytes): An unsigned 32-bit integer. The version number of the service provider-specific extensions to be used. This number is obtained by using NegotiateExtVersion. It can be zero if no device-specific extensions are used. Otherwise, the high-order word contains the major version number; the low-order word contains the minor version number.

lpPhoneCaps (4 bytes): An unsigned 32-bit integer. The size, in bytes, of a PHONECAPS packet that contains phone device capability information on successful completion of the request.

On successful completion, this field contains the offset of the packet in the VarData field.

Reserved2 (4 bytes): An unsigned 32-bit integer. This field is used for padding and MUST be ignored on receipt. It can be any value.

Reserved3 (4 bytes): An unsigned 32-bit integer. This field is used for padding and MUST be ignored on receipt. It can be any value.

Reserved4 (4 bytes): An unsigned 32-bit integer. This field is used for padding and MUST be ignored on receipt. It can be any value.

Reserved5 (4 bytes): An unsigned 32-bit integer. This field is used for padding and MUST be ignored on receipt. It can be any value.

Reserved6 (4 bytes): An unsigned 32-bit integer. This field is used for padding and MUST be ignored on receipt. It can be any value.

Reserved7 (4 bytes): An unsigned 32-bit integer. This field is used for padding and MUST be ignored on receipt. It can be any value.

Reserved8 (4 bytes): An unsigned 32-bit integer. This field is used for padding and MUST be ignored on receipt. It can be any value.

Reserved9 (4 bytes): An unsigned 32-bit integer. This field is used for padding and MUST be ignored on receipt. It can be any value.

VarData (variable): MUST be present on successful completion of the request. MUST contain a PHONECAPS packet.

The contents of this field are DWORD-aligned.