从未调用过WSASend完成例程
WSASend completion routine has never been called
我在玩Overlapped IO,突然发现我似乎是唯一一个不能鼓励Completion回调工作的人(所有声明都是关于:它有效,我不喜欢它(。
我的应用程序的想法是:客户端(telnet localhost 27015(连接到服务器,服务器开始向客户端推送大量数据。我从来没有打过CompletionCallback。
这是代码:
#include <winsock2.h>
#include <ws2tcpip.h>
#include <atomic>
#pragma comment(lib, "ws2_32.lib")
#define DATA_BUFSIZE 16384
class CSync
{
private:
CRITICAL_SECTION m_cs;
public:
CSync() { ZeroMemory(&m_cs, sizeof(m_cs)); InitializeCriticalSection(&m_cs); }
~CSync() { DeleteCriticalSection(&m_cs); ZeroMemory(&m_cs, sizeof(m_cs)); }
inline void Lock() { EnterCriticalSection(&m_cs); }
inline void Unlock() { LeaveCriticalSection(&m_cs); }
inline BOOL WINAPI TryLock() { return TryEnterCriticalSection(&m_cs); }
};
class ScopedLock
{
public:
ScopedLock(CSync& lock) : m_lock(lock) { m_lock.Lock(); }
~ScopedLock() { m_lock.Unlock(); }
private:
CSync m_lock;
};
class SendServer
{
private:
SOCKET socket;
// std::atomic<bool> busy;
char buffer[2][DATA_BUFSIZE];
CSync syncer;
WSABUF wsabuf;
OVERLAPPED overlapped;
// HANDLE socketEvent;
std::atomic_flag busy;
char toBuffer; // 0 or 1
DWORD sent;
public:
SendServer(SOCKET& sock);
virtual ~SendServer();
bool Write(char* buff);
};
static void __stdcall Produce(SendServer *server);
void CALLBACK CompletionCallback(DWORD dwError, DWORD cbTransferred, LPWSAOVERLAPPED lpOverlapped, DWORD dwFlags);
static bool run = 1;
int main(int argc, char* argv[])
{
WSADATA wsd;
struct addrinfo *result = NULL;
struct addrinfo hints;
SOCKET ListenSocket = INVALID_SOCKET;
SOCKET AcceptSocket = INVALID_SOCKET;
int err = 0;
int rc;
// Load Winsock
rc = WSAStartup((2, 2), &wsd);
if (rc != 0) {
printf("Unable to load Winsock: %dn", rc);
return 1;
}
// Make sure the hints struct is zeroed out
SecureZeroMemory((PVOID)& hints, sizeof(struct addrinfo));
// Initialize the hints to obtain the
// wildcard bind address for IPv4
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
hints.ai_flags = AI_PASSIVE;
rc = getaddrinfo(NULL, "27015", &hints, &result);
if (rc != 0) {
printf("getaddrinfo failed with error: %dn", rc);
return 1;
}
ListenSocket = WSASocket(AF_INET, SOCK_STREAM, 0, NULL, 0, WSA_FLAG_OVERLAPPED);
//socket(result->ai_family, result->ai_socktype, result->ai_protocol);
if (ListenSocket == INVALID_SOCKET) {
printf("socket failed with error: %dn", WSAGetLastError());
freeaddrinfo(result);
return 1;
}
rc = bind(ListenSocket, result->ai_addr, (int)result->ai_addrlen);
if (rc == SOCKET_ERROR) {
printf("bind failed with error: %dn", WSAGetLastError());
freeaddrinfo(result);
closesocket(ListenSocket);
return 1;
}
rc = listen(ListenSocket, 1);
if (rc == SOCKET_ERROR) {
printf("listen failed with error: %dn", WSAGetLastError());
freeaddrinfo(result);
closesocket(ListenSocket);
return 1;
}
// Accept an incoming connection request
AcceptSocket = accept(ListenSocket, NULL, NULL);
if (AcceptSocket == INVALID_SOCKET) {
printf("accept failed with error: %dn", WSAGetLastError());
freeaddrinfo(result);
closesocket(ListenSocket);
return 1;
}
printf("Client Accepted...n");
SendServer server(AcceptSocket);
HANDLE h[1];
h[0] = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)&Produce, &server, 0, NULL);
getchar();
run = 0;
WaitForMultipleObjects(1, h, TRUE, INFINITE);
return 0;
}
void __stdcall Produce(SendServer *server)
{
char buf[] = "------------------------------------------------------------------------------------------";
char s = 0;
while (run) {
buf[0] = '0' + s++;
if (s > 9)
s = 0;
server->Write(buf);
Sleep(10);
}
}
void CALLBACK CompletionCallback(DWORD dwError, DWORD cbTransferred, LPWSAOVERLAPPED lpOverlapped, DWORD dwFlags)
{
((SendServer*)(lpOverlapped->hEvent))->Write(NULL);
}
SendServer::SendServer(SOCKET& sock) : toBuffer(0)
{
socket = sock;
ZeroMemory(buffer, DATA_BUFSIZE << 1);
busy.clear();
}
SendServer::~SendServer()
{
shutdown(socket, 2);
closesocket(socket);
}
bool SendServer::Write(char* buff)
{
ScopedLock lock(syncer);
int size = strlen(buffer[toBuffer]), toAdd = 0;
if (buff == NULL) {
busy.clear();
SecureZeroMemory(buffer[!toBuffer], DATA_BUFSIZE);
}
else {
toAdd = strlen(buff);
if (size + toAdd < DATA_BUFSIZE) {
memcpy_s(buffer[toBuffer] + size, toAdd, buff, toAdd);
size += toAdd;
buffer[toBuffer][size] = 0;
return TRUE;
}
else {
printf("nCan't add anymore!n");
}
}
if (size > 0 && !busy.test_and_set()) {
wsabuf.buf = (char*)buffer[toBuffer];
wsabuf.len = size;
SecureZeroMemory(&overlapped, sizeof OVERLAPPED);
overlapped.hEvent = this;
toBuffer = !toBuffer;
size = WSASend(socket, &wsabuf, 1, &sent, 0, &overlapped, CompletionCallback);
if (size == 0) {
//return Write(NULL);
}
if (WSA_IO_PENDING != WSAGetLastError()) {
return FALSE;
}
}
return TRUE;
}
谢谢。
在可报警等待期间调用完成回调。您没有可提醒的等待,所以完成回调会排队,但永远没有机会运行。
将WaitForMultipleObjects
更改为具有WaitForMultipleObjectsEx
的循环,将Sleep
更改为SleepEx
,并传递TRUE
作为bAlertable
参数。
WSASend
文档对此进行了说明
完成例程遵循与Windows文件I/O完成例程相同的规则在线程处于可报警等待状态之前,不会调用完成例程,例如当调用fAlertable参数设置为TRUE的函数WSAWaitForMultipleEvents时可能会发生这种情况。
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