WSAGetOverlappedResult
The Windows
Sockets WSAGetOverlappedResult function returns the results of an
overlapped operation on the specified socket.
BOOL WSAGetOverlappedResult (
SOCKET s, |
|
LPWSAOVERLAPPED lpOverlapped, |
|
LPDWORD lpcbTransfer, |
|
BOOL fWait, |
|
LPDWORD lpdwFlags |
|
); |
|
Parameters
s
[in]
Identifies the socket. This is the same socket that was specified when the
overlapped operation was started by a call to WSARecv, WSARecvFrom,
WSASend, WSASendTo, or WSAIoctl.
lpOverlapped
[in] Points
to a WSAOVERLAPPED structure that was specified when the overlapped operation
was started.
pcbTransfer
[out] Points
to a 32-bit variable that receives the number of bytes that were actually
transferred by a send or receive operation, or by WSAIoctl.
fWait
[in]
Specifies whether the function should wait for the pending overlapped operation
to complete. If TRUE, the function does not return until the operation has been
completed. If FALSE and the operation is still pending, the function returns
FALSE and the WSAGetLastError function returns WSA_IO_INCOMPLETE.
lpdwFlags
[out] Points
to a 32-bit variable that will receive one or more flags that supplement the
completion status. If the overlapped operation was initiated through WSARecv
or WSARecvFrom, this parameter will contain the results value for lpFlags
parameter.
Remarks
The results
reported by the WSAGetOverlappedResult function are those of the
specified socket's last overlapped operation to which the specified
WSAOVERLAPPED structure was provided, and for which the operation's results
were pending. A pending operation is indicated when the function that started
the operation returns FALSE, and the WSAGetLastError function returns
WSA_IO_PENDING. When an I/O operation is pending, the function that started the
operation resets the hEvent member of the WSAOVERLAPPED structure to the
nonsignaled state. Then when the pending operation has been completed, the
system sets the event object to the signaled state.
If the fWait
parameter is TRUE, WSAGetOverlappedResult determines whether the pending
operation has been completed by waiting for the event object to be in the
signaled state.
Return Values
If WSAGetOverlappedResult
succeeds, the return value is TRUE. This means that the overlapped operation
has completed successfully and that the value pointed to by lpcbTransfer
has been updated. If WSAGetOverlappedResult returns FALSE, this means
that either the overlapped operation has not completed or the overlapped
operation completed but with errors, or that completion status could not be
determined due to errors in one or more parameters to WSAGetOverlappedResult.
On failure, the value pointed to by lpcbTransfer will not be updated.
Use WSAGetLastError to determine the cause of the failure (either of WSAGetOverlappedResult
or of the associated overlapped operation).
Error Codes
WSANOTINITIALISED |
A
successful WSAStartup must occur before using this function. |
WSAENETDOWN |
The network
subsystem has failed. |
WSAENOTSOCK |
The
descriptor is not a socket. |
WSA_INVALID_HANDLE |
The hEvent
field of the WSAOVERLAPPED structure does not contain a valid event object
handle. |
WSA_INVALID_PARAMETER |
One of the
parameters is unacceptable. |
WSA_IO_INCOMPLETE |
fWait is FALSE and the I/O operation has not yet
completed. |
See Also