PROTOCOL_CL_INCOMING_DROP_PARTY callback function (ndis.h)

The ProtocolClIncomingDropParty function is used by connection-oriented NDIS clients that set up multipoint connections. Such clients must have ProtocolClIncomingDropParty functions. Otherwise, such a protocol driver's registered ProtocolClIncomingDropParty function can simply return control.

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



void ProtocolClIncomingDropParty(
  [in] NDIS_STATUS DropStatus,
  [in] NDIS_HANDLE ProtocolPartyContext,
  [in] PVOID CloseData,
  [in] UINT Size


[in] DropStatus

Indicates the reason for the party to be dropped. Usually, this is NDIS_STATUS_SUCCESS if the party on the remote note initiated a close of its connection, but it could be any CM-determined status if the call manager initiated this drop-party operation due to network problems that it discovered.

[in] ProtocolPartyContext

Specifies the handle to the client's per-party context area for the party to be dropped. The client originally supplied this handle to NDIS when it called NdisClAddParty or NdisClMakeCall.

[in] CloseData

Pointer to a buffer containing a protocol-specific close message, possibly one supplied by the remote client that the call manager received over the network, or this parameter can be NULL.

When DropStatus is NDIS_STATUS_SUCCESS, this parameter is NULL if the underlying network medium does not support transfers of data when closing a connection. However, any particular call manager might define a structure to pass additional diagnostic information to its clients on drop-party operations caused by problems on the network.

[in] Size

Specifies the length, in bytes, of the buffer at CloseData, zero if CloseData is NULL.

Return value



A call to ProtocolClIncomingDropParty indicates that the one of the following has occurred:

  • The call manager has received a request over the network to close an established connection, identified by the NdisPartyHandle that the client stored in its per-party context area at ProtocolPartyContext .
  • The call manager has detected that network problems will prevent further data transfers on the established connection.
In either case, ProtocolClIncomingDropParty should carry out any protocol-determined operations for dropping the party from the client's multipoint VC. ProtocolClIncomingDropParty must call NdisClDropParty or, if this is the last remaining party on the client's multipoint VC, NdisClCloseCall.

ProtocolClIncomingDropParty should consider the NdisPartyHandle that the client obtained from NdisClAddParty or NdisClMakeCall invalid. ProtocolClIncomingDropParty can either release the client's per-party context area or prepare it for reuse in a subsequent call to NdisClAddParty.


To define a ProtocolClIncomingDropParty 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 ProtocolClIncomingDropParty function that is named "MyClIncomingDropParty", use the PROTOCOL_CL_INCOMING_DROP_PARTY type as shown in this code example:


Then, implement your function as follows:

    NDIS_STATUS  DropStatus,
    NDIS_HANDLE  ProtocolPartyContext,
    PVOID  CloseData,
    UINT  Size

The PROTOCOL_CL_INCOMING_DROP_PARTY 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_INCOMING_DROP_PARTY 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 ProtocolClIncomingDropParty (NDIS 5.1)) in Windows Vista. Supported for NDIS 5.1 drivers (see ProtocolClIncomingDropParty (NDIS 5.1)) in Windows XP.
Target Platform Windows
Header ndis.h (include Ndis.h)

See also







NdisFreeToNPagedLookasideList NdisMCmDispatchIncomingDropParty