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Thread.h類實現了像Java中的Thread類一樣的運行方法，因此每個繼承Thread的類都會運行。C++ 11線程等待
在下面的例子中運行兩個線程：Producer和Reader，第一個（Producer）在無限循環中打印一個計數器，第二個線程（Reader）1）調用等待產生，2）寫入一些int和3）通知方法。等待使用一個condition_variable變量。
問題是「producer-> wait（）;」 Reader :: run方法內部不會阻止生產者並繼續寫入，有什麼不對？
與
g++ -std=c++11 -pthread main.cpp
由於事先編譯
//in main.cpp
int main() {
Producer p ;
Reader r (&p);
p.start();
r.start();
p.join();
r.join();
cout << "end" << endl << flush;
}
類：
// in main.cpp
#include <iostream>
#include <unistd.h>
#include "Thread.h"
class Producer : public Thread {
public:
Producer() {i = 0;}
virtual void run() ;
private:
int i;
};
void Producer::run() {
while (1) {
usleep (1000);
cout << "Producer count: " << i++ << endl << flush;
};
};
讀取器類
// in main.cpp
class Reader : public Thread {
public:
Reader (Producer* p) {producer = p; i = 0;}
virtual void run() ;
private:
int i;
Producer* producer;
};
void Reader::run() {
while (1) {
usleep (1000);
i++;
if (! (i % 1000)) {
cout << "waiting Producer" << endl << flush;
producer->wait();
cout << "write 10000 int" << endl << flush;
for (int k = 0; k < 1000; k++) {
usleep (1000);
cout << " Reader: count " << k << endl << flush;
}
producer->notify();
}
};
};
Thread.h：
#ifndef THREAD_H_
#define THREAD_H_
#include <thread>
#include <mutex>
#include <condition_variable>
using namespace std;
class Runnable {
public:
virtual void run() = 0;
};
class Thread: virtual public Runnable {
private:
mutex mtx;
condition_variable cv;
thread* theThread;
Runnable * _runnable;
Runnable * execRunnable;
static void * __run (void * cthis) {
static_cast<Runnable*> (cthis)->run();
return nullptr;
}
public:
Thread() :
_runnable (nullptr) {
theThread = nullptr;
execRunnable = this;
}
virtual ~Thread() {
if (theThread) {
theThread->detach();
delete theThread;
theThread = nullptr;
}
}
void wait () {
unique_lock<std::mutex> lk (mtx);
cv.wait (lk);
}
void notify() {
cv.notify_all();
}
void start() {
if (this->_runnable != nullptr) {
execRunnable = this->_runnable;
}
if (theThread) {
delete theThread;
}
theThread = new thread (__run, execRunnable);
}
void join() {
if (theThread) {
theThread->join();
delete theThread;
theThread = nullptr;
}
}
bool isJoinable() {
return theThread->joinable();
}
void stop() {
if (theThread) {
theThread->detach();
delete theThread;
theThread = nullptr;
}
}
};
#endif