Question

关于vc++写socket，bind出错

// wConsole.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <string>
#include "iostream.h"
#include <winsock.h>
#pragma comment(lib,"ws2_32.lib")

using namespace std;

void main(int argc, char* argv[])
{
SOCKET socket1;

//InitWinsock();
WSADATA wsaData;
//int iErrorCode;
if (WSAStartup(MAKEWORD(2,1),&wsaData)) //调用Windows Sockets DLL
{
printf("Winsock无法初始化!\n");
WSACleanup();
return;
}

printf("服务器开始创建SOCKET。\n");
struct sockaddr_in local;
struct sockaddr_in from;
int fromlen =sizeof(from);
local.sin_family=AF_INET;
local.sin_port=htons(6985); ///监听端口
local.sin_addr.s_addr=inet_addr("127.0.0.1"); //inet_addr(INADDR_ANY);//INADDR_ANY; ///本机

socket1=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);

if(socket1==INVALID_SOCKET)
{
printf("Error at socket():%d\n",GetLastError());
WSACleanup(); //释放资源
return;
}

cout<<"socket："<<socket1<<endl;

int bindid = 2;
bindid = bind(socket1,(sockaddr*)&local,sizeof(local));

if(bindid==SOCKET_ERROR)
{
printf("bind() failed.\n");
closesocket(socket1);
return;
}

cout<<"bind："<<bindid<<endl;
return;

while (1)
{
char buffer[1024]="\0";
printf("waiting for message from others-------------\n");
if (recvfrom(socket1,buffer,sizeof(buffer),0,(struct sockaddr*)&from,&fromlen)!=SOCKET_ERROR)
{
printf("Received datagram from %s--%s\n",inet_ntoa(from.sin_addr),buffer);
////给cilent发信息
sendto(socket1,buffer,sizeof(buffer),0,(struct sockaddr*)&from,fromlen);

}
//Sleep(1000);
}
closesocket(socket1);

cout<<endl;
cout<<"程序无异常"<<endl;

return;
}
bind返回的总是0，这里那里错了？？

Answer 1

1.简单服务器
//#include <winsock2.h>
//#pragma comment(lib,"WS2_32.lib")
WSADATA wsd;
static UINT port=%%1;
UINT Listen(LPVOID pParam)
{
SOCKET sServer,sClient;
char buf[1024];
int retVal;
if(WSAStartup(MAKEWORD(2,2),&wsd)!=0)
{
return -1;//失败
}
sServer=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
if(INVALID_SOCKET==sServer)
{
WSACleanup();
return -1;//创建套接字失败
}
SOCKADDR_IN addrServ;
addrServ.sin_family=AF_INET;
addrServ.sin_port=htons((short)pParam);
addrServ.sin_addr.s_addr=INADDR_ANY;
retVal=bind(sServer,(LPSOCKADDR)&addrServ,sizeof(SOCKADDR_IN));
if(SOCKET_ERROR==retVal)
{
closesocket(sServer);
WSACleanup();
return -1;//绑定套接字失败
}
retVal=listen(sServer,1);
if(SOCKET_ERROR==retVal)
{
closesocket(sServer);
WSACleanup();
return -1;//开始监听失败
}
sockaddr_in addrClient;
int addrClientlen=sizeof(addrClient);
sClient=accept(sServer,(sockaddr FAR*)&addrClient,&addrClientlen);
if(INVALID_SOCKET==sClient)
{
closesocket(sServer);
WSACleanup();
return -1;//开始接受客户端连接失败
}
ZeroMemory(buf,sizeof(buf));
retVal=recv(sClient,buf,sizeof(buf),0);
if(SOCKET_ERROR==retVal)
{
closesocket(sServer);
closesocket(sClient);
WSACleanup();
return -1;//接收数据失败
}
CString %%2(buf);
closesocket(sServer);
closesocket(sClient);
WSACleanup();
return 0;
}
CWinThread *pThread=AfxBeginThread(Listen,&port);

2.简单客户端
//#include <winsock2.h>
//#pragma comment(lib,"WS2_32.lib")
WSADATA wsd;
SOCKET sHost;
SOCKADDR_IN servAddr;
char buf[1024];
int retVal;
if(WSAStartup(MAKEWORD(2,2),&wsd)!=0)
{
return -1;//失败
}
sHost=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
if(INVALID_SOCKET==sHost)
{
WSACleanup();
return -1;//创建套接字失败
}
servAddr.sin_family=AF_INET;
servAddr.sin_addr.s_addr=inet_addr(%%3);
servAddr.sin_port=htons((short)%%2);
int nServAddlen=sizeof(servAddr);
retVal=connect(sHost,(LPSOCKADDR)&servAddr,sizeof(servAddr));
if(SOCKET_ERROR==retVal) {
closesocket(sHost);
WSACleanup();
return -1;//连接服务器失败
}
ZeroMemory(buf,sizeof(buf));
strcpy(buf,%%3);
retVal=send(sHost,buf,sizeof(buf),0);
if(SOCKET_ERROR==retVal)
{
closesocket(sHost);
WSACleanup();
return -1;//向服务器发送数据失败
}
closesocket(sHost);
WSACleanup();

3.获得本机IP
//#include <winsock2.h>
//#pragma comment(lib,"WS2_32.lib")
WSADATA wsd;
if(WSAStartup(MAKEWORD(2,2),&wsd)!=0)
{
return -1;//失败
}
char szHostname[100],szHostaddress[200];
if(gethostname(szHostname,sizeof(szHostname))!=SOCKET_ERROR)
{
HOSTENT *pHostEnt=gethostbyname(szHostname);
if(pHostEnt!=NULL){
sprintf(szHostaddress,"%d.%d.%d.%d",
( pHostEnt->h_addr_list[0][0]&0x00ff ),
( pHostEnt->h_addr_list[0][1]&0x00ff ),
( pHostEnt->h_addr_list[0][2]&0x00ff ),
( pHostEnt->h_addr_list[0][3]&0x00ff ));
}
}
else
return;
CString %%1(szHostaddress);

4.端对端通信
//#include <winsock2.h>
//#pragma comment(lib,"WS2_32.lib")
WSADATA wsd;
SOCKET s;
char buf[1024];
if(WSAStartup(MAKEWORD(2,2),&wsd)!=0)
{
return -1;//失败
}
s=socket(AF_INET,SOCK_DGRAM,0);
if(s==INVALID_SOCKET)
{
WSACleanup();
return -1;//创建套接字失败
}
SOCKADDR_IN servAddr;
servAddr.sin_family=AF_INET;
servAddr.sin_addr.s_addr=inet_addr(%%1);
servAddr.sin_port=htons(INADDR_ANY);
if(bind(s,(SOCKADDR*)&servAddr,sizeof(SOCKADDR_IN))==SOCKET_ERROR)
{
closesocket(s);
WSACleanup();
return -1;//绑定套接字失败
}
int nServAddrlen=sizeof(servAddr);
ZeroMemory(buf,sizeof(buf));
if(recvfrom(s,buf,sizeof(buf),0,(SOCKADDR*)&servAddr,&nServAddrlen)==SOCKET_ERROR)
{
closesocket(s);
WSACleanup();
return -1;//接收数据失败
}
CString %%2(buf);
ZeroMemory(buf,sizeof(buf));
strcpy(buf,%%3);
SOCKADDR_IN clientAddr;
clientAddr.sin_family=AF_INET;
clientAddr.sin_addr.s_addr=inet_addr(%%4);
clientAddr.sin_port=htons((short)%%5);
int nClientlen=sizeof(clientAddr);
if(sendto(s,buf,sizeof(buf),0,(SOCKADDR*)&clientAddr,nClientlen)==SOCKET_ERROR)
{
closesocket(s);
WSACleanup();
return -1;//向服务器发送数据失败
}
closesocket(s);
WSACleanup();

5.点对点通信
//#include <winsock2.h>
//#pragma comment(lib,"WS2_32.lib")
WSADATA wsd;
SOCKADDR_IN addrServ,addrServ2;
SOCKET sServer,sClient,sHost;
int retVal;
sockaddr_in addrClient;
char buf[1024];
static UINT port=%%2;
BOOL listenerRun=TRUE;
UINT Listen(LPVOID pParam)
{
addrServ.sin_family=AF_INET;
addrServ.sin_port=htons((UINT)pParam);
addrServ.sin_addr.s_addr=INADDR_ANY;
retVal=bind(sServer,(LPSOCKADDR)&addrServ,sizeof(SOCKADDR_IN));
if(SOCKET_ERROR==retVal)
{
closesocket(sServer);
WSACleanup();
return -1;//绑定套接字失败
}
retVal=listen(sServer,1);
if(SOCKET_ERROR==retVal)
{
closesocket(sServer);
WSACleanup();
return -1;//开始监听失败
}
int addrClientlen=sizeof(addrClient);
sClient=accept(sServer,(sockaddr FAR*)&addrClient,&addClientlen);
if(INVALID_SOCKET==sClient)
{
closesocket(sServer);
WSACleanup();
return -1;//接收客户端请求失败
}
while(listenerRun)
{
ZeroMemory(buf,sizeof(buf));
retVal=recv(sClient,buf,sizeof(buf));
if(SOCKET_ERROR==retVal)
{
closesocket(sServer);
closesocket(sClient);
WSACleanup();
return -1;//接收客户端数据失败
}
CString %%4(buf);
}
}
if(WSAStartup(MAKEWORD(2,2),&wsd)!=0)
{
return -1;//失败
}
sServer=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
if(INVALID_SOCKET==sServer)
{
WSACleanup();
return -1;//创建套接字失败
}
CWinThread *pThread=AfxBeginThread(Listen,&port);
sHost=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
if(INVALID_SOCKET==sHost)
{
WSACleanup();
return -1;//创建套接字失败
}
servAddr2.sin_family=AF_INET;
servAddr2.sin_addr.s_addr=inet_addr(%%1);
servAddr.sin_port=htons((short)%%3);
int nServerAddrlen=sizeof(servAddr2);
retVal=connect(sHost,(LPSOCKADDR)&servAddr2,sizeof(servAddr2));
if(SOCKET_ERROR==retVal)
{
closesocket(sHost);
WSACleanup();
return -1;//连接失败
}
zeroMemory(buf,sizeof(buf));
strcpy(buf,%%5);
retVal=send(sHost,buf,sizeof(buf),0);
if(SOCKET_ERROR==retVal)
{
closesocket(sHost);
WSACleanup();
return -1;//向发送数据失败
}
listenerRun=FALSE;
DWORD dwExitCode;
::GetExitCodeThread(pThread->m_hThread,&dwExitCode);
pThread=null;
closesocket(sServer);
closesocket(sClient);
closesocket(sHost);
WSACleanup();

Answer 2

返回0就对了，bind调用成功后就返回0，否则返回 SOCKET_ERROR 。你差下MSDN就知道了。你的程序没有错， 是你理解错了。

Answer 3

If no error occurs, bind returns zero. Otherwise, it returns SOCKET_ERROR