Python调用C库及进程形式启动C的线程

Python调用C库的线程则比lua好多了，只是lua的体量比较小，python就要大一点，python使用ctypes调用C库(注意这里就不同于lua需要以lua形式提供c接口，python可以直接调用C形式的函数接口了并不需要引入python形式的C)，第二这里使用multiprocessing进程的方式来调用Cdll中的线程，虽然使用threading也可以完成任务，但是后者消耗的Cpu达到9%满单核运行了，而进程则没有。

1、ctypes调用Cdll库

python代码

from ctypes import *if __name__ == '__main__':pDll = CDLL("./pythonTestCDll.dll")pDll.PrintCdll()

C代码

.h文件
extern "C" __declspec(dllexport) void PrintCdll();
.cpp文件
//extern "C" __declspec(dllexport) void PrintCdll(); 这样暴露接口
void PrintCdll()
{cout << "C DLL cout :" << endl;
}

2、python中以_thread方式调用Cdll启动其中线程

python代码

from ctypes import *
import _thread
import time#以线程的方式启动Cdll
pDll = CDLL("./pythonTestCDll.dll") #加载Cdll库
pDll1 = CDLL("./pythonTestCDll.dll")
def print_time(threadName, delay):count = 0while 1:time.sleep(delay)count += 1print("%s: %s" % (threadName, time.ctime(time.time())))def testDLL( threadName, delay):pDll.startC() #调用Cdll中的函数def testDLL1( threadName, delay):pDll1.startC()if __name__ == '__main__':_thread.start_new_thread(print_time,("Thread-1", 1,))_thread.start_new_thread(testDLL, ("Thread-2", 1,))_thread.start_new_thread(testDLL1, ("Thread-3", 1,))print("start thread")#线程这样需保证主进程一直运行，如果去掉while则cdll的线程调用也会死亡while 1:pass

C代码

.h文件
extern "C" __declspec(dllexport) void startC();
.cpp文件
#include "pythonTestCDll.h"
#include <iostream>
#include <thread>
#include <string>
using namespace std;thread *th = NULL;void func()
{int num = 0;while (true){cout << "startC num :" << num++ << " flag = " << flag << endl;_sleep(1000);if (flag == 1){num = 0;}int re = 1 / num;}return;
}void startC()
{th = new thread(func);/*while (1){_sleep(10000);}*/return;
}

3、python以multiprocessing进程方式运行CDLL中的线程

从而最后可以从任务管理器中查看到每个c线程都是一个进程相当于一个exe在跑。

python代码

import multiprocessing
from multiprocessing import Process,Queue
import os
from ctypes import *
import timepDll = CDLL("./pythonTestCDll.dll")
pDll_1 = CDLL("./pythonTestCDll.dll")def testDLL():pDll.startC()while 1:time.sleep(1)print("testDLL:")def testDLL_1():pDll_1.startC()#得保证调用Cdll线程的子进程存在while死循环不然Cdll线程也会死亡while 1:time.sleep(1)print("testDLL_1:")if __name__ == '__main__':p = multiprocessing.Process(target=testDLL, args=())p.start()p = multiprocessing.Process(target=testDLL_1, args=())p.start()#使用进程的方式 则主进程没有一直运行也没有关系#while 1:#   time.sleep(1)#   print("__name__:")

C代码

.h文件
extern "C" __declspec(dllexport) void startC();
.cpp文件
#include "pythonTestCDll.h"
#include <iostream>
#include <thread>
#include <string>
using namespace std;thread *th = NULL;void func()
{int num = 0;while (true){cout << "startC num :" << num++ << " flag = " << flag << endl;_sleep(1000);if (flag == 1){num = 0;}int re = 1 / num;}return;
}void startC()
{th = new thread(func);/*while (1){_sleep(10000);}*/return;
}

4、python主进程通过multiprocessing.Queue()队列向子进程传递值从而改变Cdll的执行逻辑

python代码

import multiprocessing
from multiprocessing import Process,Queue
import os
from ctypes import *
import time
pDll = CDLL("./pythonTestCDll.dll")
pDll_1 = CDLL("./pythonTestCDll.dll")
flag = 0
def testDLL(qR, qS):pDll.startC()while 1:time.sleep(1)# 注意队列get是阻塞的，因此要先判断队列是否有值防止堵塞while qR.qsize():v = qR.get()print("testDLL:qR.size() > 0")if v == 1:print("testDLL:qR.get() %i" % v)pDll.SetFlagValue(1)else:print("testDLL:qR.get() %i" % v)qS.put("testDLL")def testDLL_1(qR, qS):pDll_1.startC()while 1:time.sleep(1)#注意队列get是阻塞的，因此要先判断队列是否有值防止堵塞#操作逻辑是如果是进程testDLL_1 取到队列值为1则不进行处理并放回队列，队列是线程安全的while qR.qsize():print("testDLL_1:qR.size() > 0")v = qR.get()if v == 1:print("testDLL_1:qR.get() %i" % v)qR.put(v)breakelse:print("testDLL_1:qR.get() %i" % v)qS.put("testDLL_1")if __name__ == '__main__':ProcessJob = []qGet = multiprocessing.Queue()  #队列是线程进程安全的无需加锁qSen = multiprocessing.Queue()p = multiprocessing.Process(target=testDLL_1, args=(qGet,qSen,))ProcessJob.append(p)p.start()  # 启动进程#p.join()  # 阻塞进程直至 当前进程中的任务完成p1 = multiprocessing.Process(target=testDLL, args=(qGet,qSen,))ProcessJob.append(p1)p1.start()  # 启动进程#p1.join()  # 阻塞进程直至 当前进程中的任务完成count = 0while 1:qGet.put(10)    #往Get队列中放值10count += 1while qSen.qsize():     #每次取值应该都取完str = qSen.get()  # 从Sen队列中取值，是那两个线程放入的print("qSen ： %s" % str)# 往Get队列中放值1，在testDLL进程中接收到1会设置CDLL的flag值从而改变线程执行，而testDLL1接收1则不做处理又再将1放入进去if count == 10:qGet.put(1)time.sleep(1)

C++代码

.h文件
extern "C" __declspec(dllexport) void startC();
extern "C" __declspec(dllexport) void SetFlagValue(int v);
.cpp文件
#include "pythonTestCDll.h"
#include <iostream>
#include <thread>
#include <string>
using namespace std;thread *th = NULL;void func()
{int num = 0;while (true){cout << "startC num :" << num++ << " flag = " << flag << endl;_sleep(1000);if (flag == 1) //如果flag为1了那么就将num设置为0{num = 0;}//int re = 1 / num;}return;
}void startC()
{th = new thread(func);/*while (1){_sleep(10000);}*/return;
}void SetFlagValue(int v)
{cout << "SetFlagValue flag : " << flag << "v = "<< v << endl;flag = v;cout << "SetFlagValue flag :  " << flag << endl;
}

5、以类多个文件的管理形式实现进程multiprocessing方式的

from DllClass import MyClass 即可导入DllClass 文件中的MyClass

python代码

DllClass.py文件
class MyClass:#成员变量name = ''id = 0state = 0pDll = 0# 构造函数def __init__(self, name, id, state):self.name = nameself.id = idself.state = state#成员方法def getState(self):return self.statedef pocD(self, name):return-----------------------------------------DllScoketClass.py文件
from ctypes import *import time
from multiprocessing import Queue
from DllClass import MyClassclass DllScoketClass(MyClass):soc = ''def __init__(self, soc, name, id, state):super(DllScoketClass, self).__init__(name, id, state)       #需显示调用父类__init__构造函数self.soc = socdef pocD(self, qR, qS):pDll = CDLL("./pythonTestCDll.dll")pDll.startC() #启动Cdll的线程#处理逻辑while 1:time.sleep(1)#接收守护进程中对队列传递的参数if qR.qsize() > 0:v = qR.get()print("DllScoketClass:qR.size() > 0")if v == 1:pDll.SetFlagValue(1) #调用CDLL的函数改变其中流程else:print("DllScoketClass:qR.size() < 0")qS.put("DllScoketClass")end--------------------------------------------------
main.py文件
import os
import time
import multiprocessing
from DllScoketClass import DllScoketClass #从DllClass.py中导入MyClass类if __name__ == '__main__':c1 = DllScoketClass("soc", "c1", 0, 0)c2 = DllScoketClass("soc2", "c2", 0, 0)print("父类方法: %i" % c1.getState())ProcessJob = []qGet = multiprocessing.Queue()qSen = multiprocessing.Queue()p = multiprocessing.Process(target=c1.pocD, args=(qGet, qSen, ))ProcessJob.append(p)p.start()  # 启动进程p = multiprocessing.Process(target=c2.pocD, args=(qGet, qSen,))ProcessJob.append(p)p.start()  # 启动进程count = 0while 1:if qSen.qsize() > 0:    #防止get阻塞进程str = qSen.get()print("qSen ： %s" % str)if count == 10:qGet.put(1)count += 1time.sleep(1)end

C++代码与上节一致

6、如Cdll崩溃需由multiprocessing再次调起

如果Cdll崩溃那么其实调用Cdll的子进程的状态也是死亡了那么就可以根据判断子进程的状态判断是否奔溃，从而进行再次调起子进程从而再次调起Cdll线程。
python代码，只有main.py代码的main函数的while中多出判断子进程状态并如果有死亡子进程则重新调起

main.py文件
# This is a sample Python script.import os
import time
import multiprocessing
from DllScoketClass import DllScoketClass #从DllClass.py中导入MyClass类if __name__ == '__main__':c1 = DllScoketClass("soc", "c1", 0, 0)c2 = DllScoketClass("soc2", "c2", 0, 0)print("父类方法: %i" % c1.getState())ProcessJob = []qGet = multiprocessing.Queue()qSen = multiprocessing.Queue()p = multiprocessing.Process(target=c1.pocD, args=(qGet, qSen, ))ProcessJob.append(p)p.start()  # 启动进程p = multiprocessing.Process(target=c2.pocD, args=(qGet, qSen,))ProcessJob.append(p)p.start()  # 启动进程count = 0while 1:if qSen.qsize() > 0:    #防止get阻塞进程str = qSen.get()print("qSen ： %s" % str)if count == 10:qGet.put(1)count += 1time.sleep(1)nums = 0while nums < len(ProcessJob):       #循环遍历所有子进程判断其状态，如果死亡则重新调起if ProcessJob[nums].is_alive() == False:  # 如果进程状态死亡那么则重新启动ProcessJob[nums].terminate()    #杀死进程ProcessJob[nums].join(0.1)      #回收print(ProcessJob)ProcessJob.remove(ProcessJob[nums])print(ProcessJob)p = multiprocessing.Process(target=c1.pocD, args=(qGet, qSen,))     #重新创建count = 0ProcessJob.append(p)p.start()       #调起print(ProcessJob)nums+=1end

7、在Cdll和python中传入传出字符串使用ctypes

python代码

import multiprocessing
from multiprocessing import Process,Queue
import os
from ctypes import *
import timepDll = CDLL("./pythonTestCDll.dll")def testDLL():pstr = create_string_buffer(1024,  '\0')    # 创建字符串缓冲区# 对输入输出参数进行声明GetAndSetString = pDll.GetAndSetStringGetAndSetString.restype = c_char_pGetAndSetString.argtypes = [c_char_p]pchar = GetAndSetString(pstr)szbuffer = c_char_p(pchar)  # 强制转换为c_char_p类型，取其value值print(pstr.value)print(szbuffer.value)if __name__ == '__main__':testDLL()

C++代码

.h文件
extern "C" __declspec(dllexport) char* GetAndSetString(char*);
.cpp文件
char* GetAndSetString(char* s)
{strcpy(s, "CDLL");char * greeting = "Cdll String";cout << "C DLL cout :" << s << endl;return greeting;
}

8、在Cdll和python相互间json字符串的相关操作

纯python内部json与python对象的转换

import json# Python 字典类型转换为 JSON 对象
data1 = {'no': 1,'name': 'Runoob','url': 'http://www.runoob.com'
}json_str = json.dumps(data1)
print("Python 原始数据：", repr(data1))
print("JSON 对象：", json_str)# 将 JSON 对象转换为 Python 字典
data2 = json.loads(json_str)
print("data2['name']: ", data2['name'])
print("data2['url']: ", data2['url'])

python代码

from ctypes import *
import time
import json#在Cdll和python中实现字符串传替
if __name__ == '__main__':pDll = CDLL("./pythonTestCDll.dll") #加载dll库data1 = {'no': 1,'name': 'Runoob','url': 'http://www.runoob.com'}data1['id'] = 12312 #添加一组元素json_str = json.dumps(data1)    #将python对象转换为json字符串传递到C端pstr = create_string_buffer(bytes(json_str, encoding='utf8'))  # 创建字符串缓冲区#对输入输出参数进行声明GetJson = pDll.GetJsonGetJson.restype = c_char_pGetJson.argtypes = [c_char_p]pchar = GetJson(pstr)szbuffer = c_char_p(pchar)#强制转换为c_char_p类型，取其value值print(pstr.value)print(szbuffer.value)data2 = json.loads(szbuffer.value) #将Cdll返回的json格式字符串进行转换为python对象print("data2['name']: ", data2['name'])print("data2['no']: ", data2['no'])print("data2['url']: ", data2['url'])

C++代码
需引入json的第三方库，配置头文件和lib文件即可

.h文件
extern "C" __declspec(dllexport) char* GetJson(const char *s);
.cpp文件
#include "pythonTestCDll.h"
#include <iostream>
#include <thread>
#include <string>
#include "json/json.h"
using namespace std;
char * GetJson(const char *s)
{//char* greeting = (char*)malloc(100);//strcpy(s, "afadsfads");char * greeting =  "{\"no\": 1, \"name\": \"Runoob\", \"url\": \"http://www.runoob.com\"}";cout <<  "C DLL cout :"<< s << endl;Json::Reader reader;Json::Value root;if (reader.parse(s, root))  // reader将Json字符串解析到root，root将包含Json里所有子元素  {std::string upload_id = root["name"].asString();  // 访问节点，int code = root["no"].asInt();    // 访问节点，cout << "CDLL cout root[name]:" << upload_id << endl;cout << "CDLL cout root[no]:" << code << endl;}return greeting;
}

9、python打包exe，注意multiprocessing打包的坑

打包命令

pip3 install pyinstaller
pyinstaller -F main.py DllClass.py DllScoketClass.py
如果有第三方库需放置exe目录才能运行

需要在main函数后调用这个才能打包exe后运行成功
if __name__ == '__main__':multiprocessing.freeze_support()    #在windows上pyinstaller打包多进程程序需要添加特殊指令

参考博客

https://www.runoob.com/python3/python3-function.html 基础知识
https://blog.csdn.net/cym1990/article/details/72583672 VS2015用C++创建动态库DLL及使用
https://www.cnblogs.com/wqpkita/p/7124930.html python 如何在一个.py文件中调用另一个.py文件的类
https://www.cnblogs.com/FMS-Shaw/p/9751838.html python多进程multiprocessing
https://www.cnblogs.com/eailoo/p/9178763.html multiprocessing的生产者消费者模型
https://docs.python.org/2/library/multiprocessing.html multiprocessing python官网文档
https://www.cnblogs.com/FHC1994/p/11421229.html Python调用DLL动态链接库——ctypes使用
https://blog.csdn.net/leishupei/article/details/114923207 进程终止及进程状态
https://www.cnpython.com/qa/56334 ctypes从c函数返回字符串
https://baijiahao.baidu.com/s?id=1615259691934668555&wfr=spider&for=pc 如何调用DLL函数之传递数值、指针与字符串参数
https://blog.csdn.net/cainiao_python/article/details/108543978 Python打包成exe
https://blog.csdn.net/lghello/article/details/105824910 Pyinstaller打包python多进程程序出错出现多个窗口