一、MutexLock 類
class MutexLock : boost::noncopyable
二、MutexLockGuard類
class MutexLockGuard : boost::noncopyable
三、Condition類
class Condition : boost::noncopyable
某個線程:
加鎖
while (條件)
wait(); //1、解鎖;2、等待通知;3、得到通知返回前重新加鎖
解鎖
另一個線程:
加鎖
更改條件
通知notify(可以移到鎖外)
解鎖
四、CountDownLatch類
class CountDownLatch : boost::noncopyable
既可以用於所有子線程等待主線程發起 “起跑” 也可以用於主線程等待子線程初始化完畢纔開始工作
下面寫兩個程序測試一下CountDownLatch 的作用:
CountDownLatch_test1:
#include <muduo/base/CountDownLatch.h> #include <muduo/base/Thread.h> #include <boost/bind.hpp> #include <boost/ptr_container/ptr_vector.hpp> #include <string> #include <stdio.h> using namespace muduo; class Test { public: Test(int numThreads) : latch_(1), threads_(numThreads) { for (int i = 0; i < numThreads; ++i) { char name[32]; snprintf(name, sizeof name, "work thread %d", i); threads_.push_back(new muduo::Thread( boost::bind(&Test::threadFunc, this), muduo::string(name))); } for_each(threads_.begin(), threads_.end(), boost::bind(&Thread::start, _1)); } void run() { latch_.countDown(); } void joinAll() { for_each(threads_.begin(), threads_.end(), boost::bind(&Thread::join, _1)); } private: void threadFunc() { latch_.wait(); printf("tid=%d, %s started\n", CurrentThread::tid(), CurrentThread::name()); printf("tid=%d, %s stopped\n", CurrentThread::tid(), CurrentThread::name()); } CountDownLatch latch_; boost::ptr_vector<Thread> threads_; }; int main() { printf("pid=%d, tid=%d\n", ::getpid(), CurrentThread::tid()); Test t(3); sleep(3); printf("pid=%d, tid=%d %s running ...\n", ::getpid(), CurrentThread::tid(), CurrentThread::name()); t.run(); t.joinAll(); printf("number of created threads %d\n", Thread::numCreated()); }
執行結果如下:
simba@ubuntu:~/Documents/build/debug/bin$ ./countdownlatch_test1 pid=2994, tid=2994 pid=2994, tid=2994 main running ... tid=2997, work thread 2 started tid=2997, work thread 2 stopped tid=2996, work thread 1 started tid=2996, work thread 1 stopped tid=2995, work thread 0 started tid=2995, work thread 0 stopped number of created threads 3 simba@ubuntu:~/Documents/build/debug/bin$
可以看到其他三個線程一直等到主線程睡眠完執行run(),在裏面執行latch_.countDown() 將計數減爲0,進而執行notifyall 喚醒後,纔開始執行下來。
CountDownLatch_test2:
#include <muduo/base/CountDownLatch.h> #include <muduo/base/Thread.h> #include <boost/bind.hpp> #include <boost/ptr_container/ptr_vector.hpp> #include <string> #include <stdio.h> using namespace muduo; class Test { public: Test(int numThreads) : latch_(numThreads), threads_(numThreads) { for (int i = 0; i < numThreads; ++i) { char name[32]; snprintf(name, sizeof name, "work thread %d", i); threads_.push_back(new muduo::Thread( boost::bind(&Test::threadFunc, this), muduo::string(name))); } for_each(threads_.begin(), threads_.end(), boost::bind(&muduo::Thread::start, _1)); } void wait() { latch_.wait(); } void joinAll() { for_each(threads_.begin(), threads_.end(), boost::bind(&Thread::join, _1)); } private: void threadFunc() { sleep(3); printf("tid=%d, %s started\n", CurrentThread::tid(), CurrentThread::name()); latch_.countDown(); printf("tid=%d, %s stopped\n", CurrentThread::tid(), CurrentThread::name()); } CountDownLatch latch_; boost::ptr_vector<Thread> threads_; }; int main() { printf("pid=%d, tid=%d\n", ::getpid(), CurrentThread::tid()); Test t(3); t.wait(); printf("pid=%d, tid=%d %s running ...\n", ::getpid(), CurrentThread::tid(), CurrentThread::name()); t.joinAll(); printf("number of created threads %d\n", Thread::numCreated()); }
執行結果輸出如下:
simba@ubuntu:~/Documents/build/debug/bin$ ./countdownlatch_test2 pid=4488, tid=4488 tid=4491, work thread 2 started tid=4491, work thread 2 stopped tid=4490, work thread 1 started tid=4490, work thread 1 stopped tid=4489, work thread 0 started pid=4488, tid=4488 main running ... tid=4489, work thread 0 stopped number of created threads 3
可以看出當其他三個線程都啓動後,各自執行一次 latch_.countDown(),主線程wait() 返回繼續執行下去。
參考:
muduo manual.pdf
《linux 多線程服務器編程:使用muduo c++網絡庫》