1. 윈속(winsock)기반 에코 서버 프로그램으로 BSD 소켓과 POSIX 인터페이스로 만들었음.
   
2. 에코 클라이언트 프로그램과 쌍으로 테스트할 수 있다.
   
   

#include <winsock.h>   
#include <stdio.h>   
   
#define MAX_PACKETLEN 512   
#define PORT 5552   
   
int main()   
{   
    WSADATA wsaData;   
    int status;   
    int SockLen;   
    int Readn,Writen;   
    SOCKET EndpointSocket, ClientSocket;   
    struct sockaddr_in SockInfo, ClientSockInfo;   
    char ReadBuffer[MAX_PACKETLEN];   
   
   
    if(WSAStartup(MAKEWORD(2,2),&wsaData)!= 0)   
    {   
        printf("error\r\n");   
        return 0;   
    }   
   
    EndpointSocket = socket( AF_INET, SOCK_STREAM, 0 );   
    if( EndpointSocket == INVALID_SOCKET )   
        return 1;   
   
    printf("Success socket create\r\n");   
    ZeroMemory(&SockInfo, sizeof( struct sockaddr_in ));   
   
    SockInfo.sin_family = AF_INET;   
    SockInfo.sin_port = htons( PORT );   
    SockInfo.sin_addr.S_un.S_addr = htonl(INADDR_ANY);   
   
    status = bind( EndpointSocket, (struct sockaddr*)&SockInfo, sizeof( struct sockaddr_in) );   
    if( status == SOCKET_ERROR)    
    {   
        printf("Bind Error\n");   
        return 0;   
    }   
    if( SOCKET_ERROR == listen( EndpointSocket, 5 ))   
    {   
        printf("listen Error\n");   
        return 0;   
    }   
   
    while(1)   
    {   
        ZeroMemory( &ClientSockInfo, sizeof( struct sockaddr_in ) );   
        SockLen = sizeof(struct sockaddr_in);   
        ClientSocket = accept( EndpointSocket, (struct sockaddr*)&ClientSockInfo, &SockLen );   
        if(ClientSocket == INVALID_SOCKET)   
        {   
            printf("Accept Error\n");   
            closesocket(EndpointSocket);   
            WSACleanup();   
            return 1;   
        }   
        printf("Accept Client\n");   
        Readn = recv( ClientSocket, ReadBuffer, MAX_PACKETLEN,0 );   
        if( Readn > 0 )   
        {   
            Writen = send( ClientSocket, ReadBuffer, Readn, 0 );   
        }   
        else   
        {   
            printf("read Error\n");   
        }   
        closesocket(ClientSocket);    
    }   
    closesocket( EndpointSocket );    
    WSACleanup();   
    return 0;   
   
}