QT(41)-多线程-QTThread-同步QSemaphore-互斥QMutex

1.QTThread
2.QSemaphore
3.QMutex

---

1.QTThread
 

 

 1.1QThread h 头文件

#ifndef MYTHREAD_H
#define MYTHREAD_H

#include <QThread>

#1.继承于public QThread
//2.虚函数run()
class MyThread:public QThread
{
   Q_OBJECT
public:
   explicit MyThread(QObkect *parent=0);
protected:
  virtual void run();
signals:
public slots:
   
};

#endif

1.2.QThread cpp文件

#include"MyThread.h"
#include<QDebug>
MyThread::MyThread(QObject *parent):QThtrad(parent)
{
}
void MyThread::run()
{
  int i=1;
  for(i=1;i<=5;i++)
  {
    qDebug()<<i;
    sleep(1);
  }
}

    1.3 main 调用文件

#include<QApplication>
#include"MainWindow.h"
#include"MyThread.h"
int main(int argc,char *argv[])
{
   QApplication a(argc,argv);
   MyThread mt;
   mt.start();

  MainWindow mw;
  mw.show();
  return  a.exec();
}

  2.同步QSemaphore

 

线程的执行顺序是由信号量的个数指定的。

 

 两个线程类
ThreadNum tn;          //打印1 2 3 
ThreadAlphabet ta;   //打印 abc
先打印 abc 再打印 1 2 3

#include<QApplication>
#include"ThreadNum.h"     
#include"ThreadAlphabet.h"

int main(int argc,char *argv[])
{
   QApplication a(argc,argv);
   ThreadNum tn;
   ThreadAlphabet ta;

   tn.start();
   ta.start();
   return a;

}

//semManager 单例的模式

#include <QSemaphore>
class SemManager
{
//1.创建两个变量
    QSemaphore semnum;     // 对应于ThreadNum
    QSemaphore semAlphabet;// 对应于ThreadAlphabet
//2.私有化单例
public:
 static SemManager *getInstance();
private:
 static SemManager  *instance;
 SemManager(); 
};
#endif

semManager.cpp

#include "SemManager.h"
SemManager  *SemManager::instance=0;
SemManager  *SemManager::getInstance()
{
    if(0==instance)
       instance=new SemManager;
    return instance;
}
SemManager::SemManager():semnum(0),semAlphabet(1)
{

}

.acquire() -1      release() +1
2.1ThreadAlphabet 调用

#include"ThreadAlphabet.h"
#include<QDebug>
#include"SemManager.h"
ThreadAlphabet::ThreadAlphabet(QObject *parent):QThtread(parent)
{
}
void ThreadAlphabet::run()
{
  int i=0;
  SemManager *sm= SemManager ::getInstance();
  for(i=0;i<=3;i++)                                  //初始值为0
  {
    sm->semAlphabet.acquire();                       //semAlphabet -1           
    qDebug()<<(char)('a'+i);
    sleep(2);
    sm->semNum.release();                            //semNum +1
  }
}

2.2ThreadNum调用

#include"ThreadNum.h"
#include<QDebug>
#include"SemManager.h"
ThreadNum::ThreadNum(QObject *parent):QThtread(parent)
{
}
void ThreadNum::run()
{
  int i=0;
  SemManager *sm= SemManager ::getInstance();
  for(i=1;i<=3;i++)                                      //初始值为1
  {
    sm->semNum.acquire();                                //semNum -1
    qDebug()<<i;
    sleep(1);
    sm->semAlphabet.release();                           //semAlphabet +1 
  }
}

3.QMutex

Ticket.h

#include <QThread>
#include <QMutex>                                //1.添加头文件
class Ticket
{
private:
   int ticketCount;
   QMutex mutex;                                //2.添加变量
public:
    Ticket(int count=1);
    void takeTicket();
};
 
class TicketThread:public QThread                //线程函数 对数量进行减操作
{
  Q_OBJECT
public:
   explicit TicketThread(QObject *parent=0);
protected:
   virtual void run();

}

Ticket.cpp

#include"TicketThread.h"
#include<QDebug>
Ticket ticket(1);
//1.Ticket
Ticket::Ticket(int count):ticketCount(count)
{
}

void Ticket::takeTicket()
{
   mutex.lock();                            //1.函数上锁
  if(ticketCount >0)
  {
     ticketCount--;
     qDebug()<<"take success,last:"<<ticketCount;
  }
   else
  {
        qDebug()<<"take failed";
  }
  
  mutex.unlock();                         //2.函数解锁
}


//2.TicketThread
TicketThread::TicketThread(QObject *parent):QThread(parent)
{
}
void TicketThread::run()
{
  ticket.takeTicket();
}

main.cpp
 

#include <QApplication>
#include "mainwindow.h"
#include "TicketThread.h"

int main(int argc, char *argv[])
{
    QApplication a(argc,argv);

    TicketThread tt1;
    TicketThread tt2;
    TicketThread tt3;
    TicketThread tt4;

    tt1.start();
    tt2.start();
    tt3.start();
    tt4.start();
   
  return a.exec();
    
}

 应该不会出现负数，但是实际上出现了。多线程时会让判断实效的。