RpcAsyncCompleteCall function (rpcasync.h)

Article
04/02/2021

The client and the server call the RpcAsyncCompleteCall function to complete an asynchronous remote procedure call.

Syntax

RPC_STATUS RpcAsyncCompleteCall(
  PRPC_ASYNC_STATE pAsync,
  void             *Reply
);

Parameters

pAsync

Pointer to the RPC_ASYNC_STATE structure that contains asynchronous call information.

Reply

Pointer to a buffer containing the return value of the remote procedure call.

Return value

In addition to the following values, RpcAsyncCompleteCall can also return any general RPC or application-specific error.

Value	Meaning
RPC_S_OK	The call was completed successfully.
RPC_S_INVALID_ASYNC_HANDLE	The asynchronous call handle is not valid.
RPC_S_ASYNC_CALL_PENDING	The call has not yet completed.
RPC_S_CALL_CANCELLED	The call was canceled.

Note For a list of valid error codes, see RPC Return Values.

Remarks

Completes the asynchronous RPC call. Both client and server call this function.

Client: Reply points to a buffer that will receive the reply. If the client calls this function before the reply has arrived, the call returns RPC_S_ASYNC_CALL_PENDING. The buffer must be valid and it must be big enough to receive the return value. If this call is successful, the [out] and the [in, out] parameters are valid. If the call does not return RPC_S_ASYNC_CALL_PENDING, this RpcAsyncCompleteCall invocation is final for the RPC call. After this function call, regardless of success or failure, all resources allocated by the RPC runtime are freed. Subsequent calls to the RpcAsyncCompleteCall or RpcAsyncCancelCall functions have undefined results until a new call on the RPC_ASYNC_STATE structure is initiated.

Server: Reply points to a buffer that contains the return value that needs to be sent to the client. You only need to set a valid buffer for Reply if your function is declared with a return type. Before a call to RpcAsyncCompleteCall is made, the [out] and [in, out] parameters must be updated. These parameters, and the asynchronous handle, should not be touched after the call to RpcAsyncCompleteCall returns. The invocation of RpcAsyncCompleteCall on the server is final. If the RpcAsyncCompleteCall function call fails, the RPC runtime frees the parameters.

Any [out] parameters, including [comm_status] and [fault_status] parameters, are only valid if the return value of RpcAsyncCompleteCall is RPC_S_OK.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps \| UWP apps]
Minimum supported server	Windows 2000 Server [desktop apps \| UWP apps]
Target Platform	Windows
Header	rpcasync.h (include Rpc.h)
Library	Rpcrt4.lib
DLL	Rpcrt4.dll