pythonUDP发送结构体，对齐到C++结构体

给出程序先：

import random import socket import struct import threading import pickle import json from struct import * from time import sleep   class sendMsg:     def __init__(self):         self.sendType=b'\x01'#ready         self.cliType=b'\x01'         self.lonDir=b'E'         self.latDir=b'N'         self.cliNum=1         self.lonDeg=100         self.lonMin=100         self.lonSec=100         self.latDeg=100         self.latMin=100         self.latSec=100         self.year=2019         self.month=9         self.day=6         self.hour=12         self.minute=10         self.second=10         self.ipFirst=192         self.ipSecond=168         self.ipThird=6         self.ipFourth=108         self.typeStr='cccciiiiiiiiiiiiiiiii'      def __str__(self):         return self.cliNum class RecMsg():     def __init__(self):         self.id=b'\x02'         self.ipFirst=192         self.ipSecond=168         self.ipThird=6         self.ipFourth=108         self.port=-1         self.errorType=b'\x01'         self.bandWidth=-1         self.typeStr='=ciiiiici'   class CommunateThread(threading.Thread):  # 继承父类threading.Thread     def __init__(self, id,packetLoss,socket,localIP,localPort,remoteIP,remotePort,file):         threading.Thread.__init__(self)         self.id=id         self.packetLoss=packetLoss         self.socket=socket         self.localIP = localIP         self.localPort=localPort         self.remoteIP = remoteIP         self.remotePort=remotePort         self.file=file     def run(self):  # 把要执行的代码写到run函数里面 线程在创建后会直接运行run函数         connect=False         while True:             if not connect:                 self.sendConnect()             data, addr = self.socket.recvfrom(1024)             print("接收到{}发送的消息{}".format(addr,data))             recMes = RecMsg()             recData = struct.unpack(recMes.typeStr,data)             print(recData)             if recData[0]==b'\x01' or (recData[0]==b'\x03' and recData[6]==b'\x01'):                 self.sendFile(recData)     def readFile(self):         with open(self.file,"rb") as f:             data = f.read(1024)             while data:                 yield data                 data=f.read(1024)     def sendFile(self,recData):         ip = "{}.{}.{}.{}".format(recData[1],recData[2],recData[3],recData[4])         port = recData[5]         try:             s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)             i =1             for data in self.readFile():                 p = random.randint(1,100)                 if p<self.packetLoss:                     continue                 s.sendto(data,(ip,port))                 sleep(0.005)                 i+=1                 if i%1000:                     print(i," : send to {}:{},1k".format(ip,port))              print("发送完成，总计发送 {} K".format(i))         except Exception as e:             print(e)     def sendConnect(self):         connect =sendMsg()         connect.cliNum=self.id         data=pack(  connect.typeStr,                     connect.sendType,                     connect.cliType,                     connect.lonDir,                     connect.latDir,                     connect.cliNum,                     connect.lonDeg,                     connect.lonMin,                     connect.lonSec,                     connect.latDeg,                     connect.latMin,                     connect.latSec,                     connect.year,                     connect.month,                     connect.day,                     connect.hour,                     connect.minute,                     connect.second,                     connect.ipFirst,                     connect.ipSecond,                     connect.ipThird,                     connect.ipFourth)         #data=pack('ccccb',connect.sendType,connect.cliType,connect.lonDir,connect.lonDir,connect.year)         print(data)         self.socket.sendto(data,(self.remoteIP,self.remotePort))         print("send to {}:{}\t\n{}".format(self.remoteIP,self.remotePort,connect.__str__())) def print_time(threadName, delay, counter):     pass

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急着把消息发出去，所以代码有点乱，也没有注释，嘻嘻。

我们知道python 使用UDP发送消息，只能发送byte出去。那么，如何和一个c++（c#）的结构体进行打包和解包呢？使用pack和unpack就可以了。

比如说我们的结构体是这样的