PROTOCOL_CL_MODIFY_CALL_QOS_COMPLETE callback function (ndis.h)

The ProtocolClModifyCallQoSComplete function is used by connection-oriented NDIS clients that can modify the quality of service on a connection dynamically. Such clients must have ProtocolClModifyCallQoSComplete functions to complete the asynchronous operations that they initiate with NdisClModifyCallQoS. Otherwise, such a protocol driver's registered ProtocolClModifyCallQoSComplete function can simply return control.

Note  You must declare the function by using the PROTOCOL_CL_MODIFY_CALL_QOS_COMPLETE type. For more information, see the following Examples section.



void ProtocolClModifyCallQosComplete(
  [in] NDIS_STATUS Status,
  [in] NDIS_HANDLE ProtocolVcContext,
  [in] PCO_CALL_PARAMETERS CallParameters


[in] Status

Specifies the final status of the client's asynchronous request to modify the call parameters for this VC as one of the following:


The QoS was modified as requested by the client.


NDIS or the call manager could not modify the QoS because one of them could not allocate sufficient resources dynamically.


The call parameters that the client supplied to NdisClModifyCallQoS were invalid.


The call manager could not change the QoS because of a failure on the network or in another connection-oriented network component.


The call manager failed to change the QoS, and NDIS propagated the CM-determined failure status to the client.

[in] ProtocolVcContext

Specifies the handle to the client's per-VC context area, which the client originally supplied to NDIS when it called NdisCoCreateVc to set up the VC for its outgoing call request or from its ProtocolCoCreateVc function if the client accepted an incoming call on this VC.

[in] CallParameters

Pointer to a buffered CO_CALL_PARAMETERS structure containing the client-specified QoS change it requested, or, possibly, the original QoS for this VC established when the connection was activated, which the call manager has restored.

Return value



A call to ProtocolClModifyCallQoSComplete indicates that the call manager has completed processing of a client-initiated request to change the quality of service on an active VC. For example, if the underlying network medium supports dynamic QoS changes, a client can request modifications at any time on an active VC.

If the client's call to NdisClModifyCallQoS succeeds, ProtocolClModifyCallQoSComplete can accept the QoS change by simply returning control. Otherwise, ProtocolClModifyCallQoSComplete can engage in further negotiation with the call manager as long as the client's developer places some reasonable limit on the number of possible renegotiations. Alternatively, ProtocolClModifyCallQoSComplete can simply tear down the call with NdisClCloseCall whenever the call manager rejects a request to change the QoS and the previously established QoS has become unacceptable to the client.


To define a ProtocolClModifyCallQoSComplete function, you must first provide a function declaration that identifies the type of function you're defining. Windows provides a set of function types for drivers. Declaring a function using the function types helps Code Analysis for Drivers, Static Driver Verifier (SDV), and other verification tools find errors, and it's a requirement for writing drivers for the Windows operating system.

For example, to define a ProtocolClModifyCallQoSComplete function that is named "MyClModifyCallQoSComplete", use the PROTOCOL_CL_MODIFY_CALL_QOS_COMPLETE type as shown in this code example:


Then, implement your function as follows:

    NDIS_STATUS  Status,
    NDIS_HANDLE  ProtocolVcContext,
    PCO_CALL_PARAMETERS  CallParameters

The PROTOCOL_CL_MODIFY_CALL_QOS_COMPLETE function type is defined in the Ndis.h header file. To more accurately identify errors when you run the code analysis tools, be sure to add the Use_decl_annotations annotation to your function definition. The Use_decl_annotations annotation ensures that the annotations that are applied to the PROTOCOL_CL_MODIFY_CALL_QOS_COMPLETE function type in the header file are used. For more information about the requirements for function declarations, see Declaring Functions by Using Function Role Types for NDIS Drivers.

For information about Use_decl_annotations, see Annotating Function Behavior.


Minimum supported client Supported for NDIS 6.0 and NDIS 5.1 drivers (see ProtocolClModifyCallQoSComplete (NDIS 5.1)) in Windows Vista. Supported for NDIS 5.1 drivers (see ProtocolClModifyCallQoSComplete (NDIS 5.1)) in Windows XP.
Target Platform Windows
Header ndis.h (include Ndis.h)

See also