Winsock编程补遗

1.UDP不需要listen函数

Sockets that are connection oriented, those of type SOCK_STREAM for example, are used with listen.

 

2.
SOCKADDR_IN和sockaddr_in数据结构等价。
SOCKADDR适用于任何协议族
SOCKADDR_IN只只适用于AF_INET

 

3.初始化SOCKADDR_IN
dest.sin_family = AF_INET;
dest.sin_port   = htons(50000); 
dest.sin_addr.s_addr = inet_addr("127.0.0.1");//其中s_addr是个宏

4.从机器名得到地址
LPHOSTENT lpHost = gethostbyname(“www.baidu.com”);

// Setup destination socket address
saDest.sin_addr.s_addr = *(PINT)lpHost->h_addr;//其中h_addr是个宏
saDest.sin_family = AF_INET;
saDest.sin_port = 0;

 

5.IP地址和字符串相互转换
inet_ntoa(saDest.sin_addr)//转换成字符串
inet_addr(“127.0.0.1”)//转换成IP地址

6.得到host名字
gethostname

 

7.判断是否可读
int IsSocketReadible(SOCKET &s)
{
    struct timeval Timeout;
    fd_set readfds;

    readfds.fd_count = 1;
    readfds.fd_array[0] = s;
    Timeout.tv_sec = 1;
    Timeout.tv_usec = 0;

    return(select(1, &readfds, NULL, NULL, &Timeout));
}