socket的服务器/客户端已经连接，但是一send/recv就出错。为何?该怎么处理

int _tmain(int argc, _TCHAR* argv[])
{
    WSADATA wsa;
    if(0!=WSAStartup(MAKEWORD(2,2),&wsa))return 1;
    SOCKET sockSrv=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);//IPPROTO_TCP和0的区别在哪里?
    if(sockSrv==INVALID_SOCKET)return 1;
    SOCKADDR_IN sAddr;
    sAddr.sin_family=AF_INET;
    sAddr.sin_port  =htons(34567);
    sAddr.sin_addr.S_un.S_addr =htonl(INADDR_ANY);
    if(SOCKET_ERROR == bind( sockSrv, (LPSOCKADDR)&sAddr, sizeof( SOCKADDR )))return 1;
    if(SOCKET_ERROR == listen(sockSrv,0))return 1;//backlog的作用是什么?
    int cbAddr = sizeof(SOCKADDR);
    while(1){
        SOCKET hAccSocket = accept(sockSrv, (SOCKADDR*)&sAddr, &cbAddr );
        if(hAccSocket==INVALID_SOCKET)return 1;
        printf("Accepted!\n");
        while(1){
            if(SOCKET_ERROR == send(sockSrv,"Hi",3,0) ){
                printf("send error\n");
                break;
            }
            printf("data sent\n");
        }
        closesocket(hAccSocket);
    }
    WSACleanup();
    return 0;
}

int _tmain(int argc, _TCHAR* argv[])
{
    WSADATA wsaData;
    if(0!=WSAStartup(MAKEWORD(2,2), &wsaData ))return 1;
    SOCKET hClient=socket(AF_INET,SOCK_STREAM,0);
    if(hClient==INVALID_SOCKET)return 1;
    SOCKADDR_IN sAddr;
    sAddr.sin_family=AF_INET;
    sAddr.sin_port  =htons(34567);
    sAddr.sin_addr.S_un.S_addr =inet_addr("127.0.0.1");
    if( SOCKET_ERROR==connect( hClient, (LPSOCKADDR)&sAddr, sizeof(SOCKADDR) ) )return 1;
    while(1){
        char buf[10]={0};
        if(0>=recv(hClient,buf,10,0)){
            printf("recv error\n");
            break;
        }
        printf("received %s\n",buf);
        Sleep(5000);
    }
    closesocket(hClient);
    WSACleanup();
    return 0;
}

if(SOCKET_ERROR == send(sockSrv,"Hi",3,0) ){
                printf("send error\n");
                break;