c++的socket编程，无客户端连接accept却不阻塞，直接返回了，怎么解决

以下是服务端的代码：

 #include "stdafx.h"
#include "winsock2.h"
#include "iostream"
#pragma comment (lib,"ws2_32")

using namespace std;
int _tmain(int argc, _TCHAR* argv[])
{
    WSADATA wsadata;
    WSAStartup(MAKEWORD(2, 2), &wsadata);
    cout << "开始创建套接字\n";
    SOCKET s = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
    struct sockaddr_in  saddrin;

    saddrin.sin_addr.S_un.S_addr = inet_addr("INADDR_ANY");
    saddrin.sin_port = htons(9100);

    cout << "开始绑定\n";
    bind(s, (sockaddr *)&saddrin, sizeof(saddrin));

    cout << "开始监听\n";
    listen(s, SOMAXCONN);



    struct sockaddr_in sClient;
    int num = sizeof(sClient);
    SOCKET client=  accept(s, (sockaddr *)&sClient, &num);
    if (client)
    {
        cout << "已接受来自客户端的连接\n";
        cout << sClient.sin_port<<'\n';

        cout<< inet_ntoa(sClient.sin_addr)<<'\n';

        char msg[MAXBYTE] = { 0 };

        recv(client, msg, sizeof(msg), 0);
        cout << msg;


        strcpy_s(msg, "this is a reply for the test\n");
        send(client, msg, strlen(msg) + sizeof(char), 0);
        cout << "已发送消息\n";


    }
    else
    {
        cout << "无客户端的连接";
    }
    system("PAUSE");
    return 0;
}

运行结果如下：

启动了服务端，客户端都没启动，就直接执行完返回了，accept那里不是应该阻塞，等待客户端的连接的吗？即使同时启动客户端和服务端也是这样的结果，请问应该怎么解决？