# include & lt; Winsock2. H> 
# include & lt; iostream> 
# include & lt; Vector> 
# include & lt; Mswsock. H> 
using namespace std; 
# define PORT 4567 
# define MAXBUFFER 1024 
# pragma comment (lib, "ws2_32. Lib") 

Typedef struct _SOCKOBJ 
{
Int nOperationType; 
The SOCKET sAccept; 
OVERLAPPED ol; 
Char Buff [MAXBUFFER]; 
Char * lpBuff; 
DWORD dwLen; 
_SOCKOBJ () 
{
ZeroMemory (& amp; Ol, sizeof (OVERLAPPED)); 
ZeroMemory (Buff, sizeof (MAXBUFFER)); 
NOperationType=0; 
SAccept=INVALID_SOCKET; 
LpBuff=Buff; 
DwLen=0; 
Ol. HEvent=WSACreateEvent (); 
} 
} * PSOCKOBJ SOCKOBJ; 

DWORD dwTotal=0, dwIndex=0; 
Vector MSKObj; 
HANDLE events [WSA_MAXIMUM_WAIT_EVENTS]; 

Void InitSock () 
{
WSADATA WSADATA; 
LPFN_ACCEPTEX lpfnAcceptEx; 
To: : WSAStartup (MAKEWORD (2, 2), & amp; WSAData); 
The SOCKET sListen=: : WSASocket (AF_INET, SOCK_STREAM, 0, NULL, 0, WSA_FLAG_OVERLAPPED); 
Sockaddr_in in_service; 
: : ZeroMemory (& amp; In_service, sizeof (sockaddr_in)); 
In_service. Sin_family=AF_INET; 
In_service. Sin_port=: : ntohs (4567); 
In_service. Sin_addr. S_un. S_addr=: : inet_addr (" 192.168.1.102 "); 
Int ret=bind (sListen, (sockaddr *) & amp; In_service, sizeof (sockaddr_in)); 
If (ret==INVALID_SOCKET) 
{
cout <"The bind error" & lt; <"\ n"; 
} 
Listen (sListen, 5); 

GUID GuidAcceptEx=WSAID_ACCEPTEX; 
DWORD dwBytes; 
(sListen WSAIoctl SIO_GET_EXTENSION_FUNCTION_POINTER, 
& GuidAcceptEx, sizeof (GuidAcceptEx), & amp; LpfnAcceptEx, sizeof (lpfnAcceptEx), & amp; DwBytes, NULL, NULL); 

for(int i=0; i<5; I++) 
{
PSOCKOBJ obj=new SOCKOBJ (); 
Obj - & gt; NOperationType=1; 
Obj - & gt; SAccept=: : WSASocket (AF_INET, SOCK_STREAM, 0, NULL, 0, WSA_FLAG_OVERLAPPED); 
LpfnAcceptEx (sListen, obj - & gt; SAccept, obj - & gt; LpBuff, 
MAXBUFFER - 2 * (sizeof (sockaddr_in) + 16), 
Sizeof (sockaddr_in) + 16, 
Sizeof (sockaddr_in) + 16, 
& Obj - & gt; DwLen, 
& Obj - & gt; Ol); 
Obj mSKObj. Push_back (*); 
Events [dwTotal++]=obj - & gt; Ol. HEvent; 
} 

While (true) 
{
//dwIndex each time returns 0 
DwIndex==: : WSAWaitForMultipleEvents (dwTotal, events, FALSE, WSA_INFINITE, FALSE); 
cout <"Code:" & lt; If (dwIndex==WSA_WAIT_FAILED) 
{
cout <" WSAWaitForMultipleEvents failed! \ n "; 
} 
DwIndex=dwIndex - WSA_WAIT_EVENT_0; 
For (int I=dwIndex; i{
DwIndex=WSAWaitForMultipleEvents (1, & amp; Events [I], FALSE, 0, FALSE); 
If (dwIndex==WSA_WAIT_TIMEOUT) 
{
continue; 
} 
: : WSAResetEvent (events [I]); 
DWORD dwTrans=0; 
DWORD dwFlags=0; 
SOCKOBJ obj=mSKObj. At (I); 
//bRet always returns False and GetLastError==996 
BOOL bRet=: : WSAGetOverlappedResult (obj. SAccept, & amp; Obj. Ol, & amp; DwTrans, FALSE, & amp; DwFlags); 
cout <"Receiving data length:" & lt; if(! BRet) 
{
DWORD err=: : GetLastError (); 
cout <"WSAGetOverlappedResult failed! \ n "; 
} 
} 
} 
} 

Void main () 
{
InitSock (); 
} 

-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

//dwIndex each time returns 0

//bRet always returns False and GetLastError==996

CodePudding user response:

996 - WSA_IO_INCOMPLETE
Overlapped I/O event object is not in A state of signalling, the Wi n 3 2 errors are closely related and overlapped I/O operations, in the call Ov W S A G e t e r l A p p e d r e S u l t S function of time, points out that the overlapped I/O operation has not yet been completed,

CodePudding user response:

I know it's overlapped I/O operation has not yet been completed,
But what is the specific I/O operation has been finished, what cause errors,

CodePudding user response:

BOOL WSAAPI WSAGetOverlappedResult (
__in SOCKET s,
__in LPWSAOVERLAPPED lpOverlapped,
__out LPDWORD lpcbTransfer,
__in BOOL fWait,
__out LPDWORD lpdwFlags
);

The Parameters
S
A descriptor identifying 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
A pointer to A WSAOVERLAPPED structure that was specified when the overlapped operation was started. This parameter must not be A NULL pointer.

LpcbTransfer
32 - bit A pointer to A variable that receives the number of bytes that were later transferred by A send or receive operation, or by WSAIoctl. This parameter must not be A NULL pointer.

FWait

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