当一个应用程序调用了一个阻塞的Windows Sockets API操作时,Windows Sockets的实现启动该操作,然后进入了和下列伪代码相似的循环:

                for(;;) {

                        /* flush messages for good user response */

                        while(BlockingHook())

                                   ;

                        /* check for WSACancelBlockingCall() */