NDK_RESULT_EX structure (ndkpi.h)

The NDK_RESULT_EX structure returns the results for an NDK request operation. It is identical to the NDK_RESULT structure, except that it has additional Type and TypeSpecificCompletionOutput members.

Syntax

typedef struct _NDK_RESULT_EX {
  NTSTATUS           Status;
  ULONG              BytesTransferred;
  PVOID              QPContext;
  PVOID              RequestContext;
  NDK_OPERATION_TYPE Type;
  ULONG              ProviderErrorCode;
  ULONG_PTR          TypeSpecificCompletionOutput;
} NDK_RESULT_EX;

Members

Status

The NDK request completion status.

BytesTransferred

The number of bytes transferred. The value of this member is valid only for NdkReceive (NDK_FN_RECEIVE) request completions. The member is undefined for all other NDK request completions.

QPContext

A context value for all requests that are posted over a queue pair (QP). The NDK consumer specified this pointer when it called the NdkCreateQp (NDK_FN_CREATE_QP) function to create the NDK_QP object.

RequestContext

A request context value specified by the NDK consumer when a request is posted.

Type

An NDK_OPERATION_TYPE enumeration value that specifies the type of operation that is being completed.

ProviderErrorCode

If Status returns STATUS_SUCCESS, then ProviderErrorCode must be zero.

If Status does not return STATUS_SUCCESS, then zero indicates the NDK provider does not support the ProviderErrorCode capability yet or did not provide an error code. A non-zero value provides additional provider information to diagnose the Status code.

ProviderErrorCode uses padding that's only available on 64-bit systems. On 32-bit systems, this padding isn't available, and when ProviderErrorCode returns zero, it can cause null pointers. This issue occurs when memory is cast incorrectly as the value for the TypeSpecificCompletionOutput pointer. It's important to note that the interface contract is broken if the Provider uses an NDK 2.1 memory layout that includes ProviderErrorCode, while the Consumer still uses an NDK 2.0 memory layout without this new field. Therefore, this structure is no longer backwards compatible for 32-bit systems between 2.1 and pre-2.1 versions.

TypeSpecificCompletionOutput

The type-specific completion output, if any. If the Type member is NdkOperationTypeReceiveAndInvalidate, this member is a 32-bit field, which contains the token to be invalidated before signaling this completion. Otherwise, this member is undefined.

Requirements

See also

NDK_FN_CREATE_QP

NDK_OPERATION_TYPE

NDK_QP

NDK_RESULT