我尝试使我的服务器单线程并发不起作用

Question

这是我接受客户的单线程迭代代码：

static int            msock           = -1;
static volatile bool  listenerRunning = true;


static void
ServerListenerLoop(void)
    while (listenerRunning) {
        int ssock;
        struct sockaddr_storage cliAddr;
        socklen_t cliAddrLen = sizeof cliAddr;

        ssock = accept(msock, (struct sockaddr *)&cliAddr, &cliAddrLen);

        if (ValidateClientSocket(ssock)) {
            Server(ssock);
    }
  }
}

我使用select函数修改代码如下，以便任意数量的客户端可以同时连接服务器并与服务器交互（不工作）：

static void
ServerListenerLoop(void)
{

    struct sockaddr_in fsin;    /* the from address of a client        */
    int        msock;           /* master server socket                */
    fd_set     rfds;            /* read file descriptor set        */
    fd_set     fds;             /* active file descriptor set        */

    int        fd, nfds;

    nfds = getdtablesize();
    FD_ZERO(&afds);
    FD_SET(msock, &afds);

    while (listenerRunning) {

        memcpy(&rfds, &afds, sizeof(rfds));

        if (select(nfds, &rfds, (fd_set *)0, (fd_set *)0,
                (struct timeval *)0) < 0)
            errexit("select: %s\n", strerror(errno));
        if (FD_ISSET(msock, &rfds)) {
            int ssock;
            struct sockaddr_storage cliAddr;
            socklen_t cliAddrLen = sizeof cliAddr;

            ssock = accept(msock, (struct sockaddr *)&cliAddr, &cliAddrLen);

            if (ssock < 0)
                errexit("accept: %s\n", strerror(errno));
            FD_SET(ssock, &afds);
        }

        for (fd=0; fd<nfds; ++fd)
            if (fd != msock && FD_ISSET(fd, &rfds)) {
                (void) close(ssock);
                FD_CLR(fd, &afds);
            }

        if (ValidateClientSocket(ssock)) {   /*VALIDATES THE CLIENT SOCKET*/
            Server(ssock);
        }
    }
}

请指导我解决我的问题