윈속 멀티스레드 서버 (Winsock)

#pragma comment(lib,"ws2_32.lib")
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <winsock2.h>
#include <process.h>
#define BUFSIZE 1024

int main(int argc, char** argv){
    WSADATA wsaData;
    SOCKET hServSock;
    SOCKET hClntSock;

    HANDLE hThread;
    DWORD dwThreadID;

    SOCKADDR_IN servAddr;
    SOCKADDR_IN clntAddr;
    int clntAddrSize;

    if(argc != 2){
        printf("Usage: %s <port> \n", argv[0]);
        exit(1);
    }
    if(WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
        ErrorHandling("WSAStartup() error!");

    hServSock = socket(PF_INET, SOCK_STREAM, 0);
    if(hServSock == INVALID_SOCKET)
        ErrorHandling("socket() error");

    memset(&servAddr, 0, sizeof(servAddr));
    servAddr.sin_family = AF_INET;
    servAddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servAddr.sin_port = htons(atoi(argv[1]));

    if(bind(hServSock, (SOCKADDR*)&servAddr, sizeof(servAddr)) == SOCKET_ERROR)
        ErrorHandling("bind() error");

    if(listen(hServSock, 5) == SOCKET_ERROR)
        ErrorHandling("listen() error");

    while(1){
        clntAddrSize = sizeof(clntAddr);
        hClntSock = accept(hServSock, (SOCKADDR*)&clntAddr, &clntAddrSize);
        if(hClntSock == INVALID_SOCKET)
            ErrorHandling("accept() error");

        printf("연결 요청: %s:%d \n", inet_ntoa(clntAddr.sin_addr), ntohs(clntAddr.sin_port));

        hThread = (HANDLE)_beginthreadex(NULL, 0, ClntConnect, (void*)hClntSock, 0, (unsigned int*)&dwThreadID);
        if(hThread == 0){
            puts("쓰레드 생성");
            exit(1);
        }
    }

    WSACleanup();
    return 0;
}

DWORD WINAPI ClntConnect(void* arg){
    SOCKET hClntSock = (SOCKET)arg;
    char buf[BUFSIZE];

    recv(hClntSock, buf, BUFSIZE, 0);
    send(sock, protocol, strlen(protocol), 0); 

    return 0;
}

void ErrorHandling(char* message){
    fputs(message, stderr);
    fputc('\n', stderr);
    exit(1);
}