/**********************************************************************

 * Python UDP broadcast PermissionError: [Errno 13] Permission denied

 * 说明：

 *     使用Python3做UDP广播，遇到这个权限问题，当时就一阵惊讶，第一看

 * 到这种无权限的问题。

 *

 *                                  2016-12-10 深圳 南山平山村 曾剑锋

 *********************************************************************/

一、参考文档：

    Python socket.error: [Errno 13] Permission denied

        http://*.com/questions/11457676/python-socket-error-errno-13-permission-denied

二、错误：

    1. 错误现象：

        [zengjf@root ~]#  python main.py

        fdsaf

        Traceback (most recent call last):

          File "main.py", line 11, in <module>

            s.sendto('zengjf'.encode('utf-8'), address)

        PermissionError: [Errno 13] Permission denied

        [zengjf@root ~]#

    2. 错误原因：

        Set the SO_BROADCAST option, if you actually mean to send to a broadcast address:

            s.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)

    3. 测试代码：

        import socket

        address = ('255.255.255.255', 50000)

        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

        s.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)

        while True:

            msg = input()

            if not msg:

                break

            s.sendto('zengjf'.encode('utf-8'), address)

        s.close()