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小編給大家分享一下C++中Boost多線程、線程同步的示例分析，相信大部分人都還不怎么了解，因此分享這篇文章給大家參考一下，希望大家閱讀完這篇文章后大有收獲，下面讓我們一起去了解一下吧！
線程的創建 boost_thread,boost_system 多線程的創建 線程的參數傳遞 線程的創建方式 線程的join 加入join,回收線程 線程中斷 線程中斷2, 線程組 boost 線程的死鎖 boost 線程遞歸鎖 線程互斥鎖,線程同步 unique_lock 鎖,離開作用域自動釋放 unique_lock 鎖 示例 2,可以顯式的釋放鎖 boost 1次初始化 boost 條件變量 boost 線程鎖,一個賬戶往另外一個賬戶轉錢案例 boost upgrade_lock
知識背景:
理解什么是線程,什么是進程,區別是什么,如何使用多進程多線程
線程的創建 boost_thread,boost_system
chunli@Linux:~/boost$ cat main.cpp
#include <iostream>
#include <boost/thread.hpp>
using namespace std;
void fun()
{
cout << "Hello Boost threads !" << endl;
}
int main()
{
boost::thread t1(fun);
t1.join();
return 0;
}
chunli@Linux:~/boost$ g++ main.cpp -l boost_thread -l boost_system && ./a.out
Hello Boost threads !
chunli@Linux:~/boost$多線程的創建
chunli@Linux:~/boost$ cat main.cpp
#include <iostream>
#include <boost/thread.hpp>
using namespace std;
void fun1(){cout << "Hello Boost threads 1!" << endl;}
void fun2(){cout << "Hello Boost threads 2!" << endl;}
void fun3(){cout << "Hello Boost threads 3!" << endl;}
int main()
{
boost::thread t1(fun1); t1.join();
boost::thread t2(fun2); t2.join();
boost::thread t3(fun3); t3.join();
return 0;
}
chunli@Linux:~/boost$ g++ main.cpp -l boost_thread -l boost_system && ./a.out
Hello Boost threads 1!
Hello Boost threads 2!
Hello Boost threads 3!
chunli@Linux:~/boost$線程的參數傳遞
chunli@Linux:~/boost$ cat main.cpp
#include <iostream>
#include <boost/thread.hpp>
using namespace std;
void fun1(const int &id){cout << "threads id "<<id << endl;}
void fun2(const int &id){cout << "threads id "<<id << endl;}
void fun3(const int &id){cout << "threads id "<<id << endl;}
int main()
{
boost::thread t1(fun1,1); t1.join();
boost::thread t2(fun2,2); t2.join();
boost::thread t3(fun3,3); t3.join();
return 0;
}
chunli@Linux:~/boost$ g++ main.cpp -l boost_thread -l boost_system && ./a.out
threads id 1
threads id 2
threads id 3
chunli@Linux:~/boost$線程的創建方式
chunli@Linux:~/boost$ cat main.cpp
#include <iostream>
#include <boost/thread.hpp>
using namespace std;
void fun1(const int &id)
{
cout << "threads id "<<id << endl;
}
struct MyThread
{
void operator()(const int &id)
{
cout << "threads id "<<id << endl;
}
void fun(const int &id)
{
cout << "threads id "<<id << endl;
}
};
int main()
{
boost::thread t1(fun1,1);//自由函數
t1.join();
MyThread mythread;
boost::thread t2(mythread,2);//函數對象
t2.join();
boost::thread t3(&MyThread::fun,mythread,3); //成員函數
t3.join();
boost::thread t4(MyThread(),4); //臨時對象
t4.join();
boost::thread t5(boost::ref(mythread),5);//對象引用
t5.join();
return 0;
}
chunli@Linux:~/boost$ g++ main.cpp -l boost_thread -l boost_system && ./a.out
threads id 1
threads id 2
threads id 3
threads id 4
threads id 5
chunli@Linux:~/boost$線程的join
chunli@Linux:~/boost$ cat main.cpp
#include <iostream>
#include <boost/thread.hpp>
using namespace std;
void fun1(const int &id){cout << "threads id "<<id << endl;}
int main()
{
boost::thread t1(fun1,1);
//t1.join();
cout << "main end!" << endl;
return 0;
}
chunli@Linux:~/boost$ g++ main.cpp -l boost_thread -l boost_system && ./a.out
main end!
chunli@Linux:~/boost$ g++ main.cpp -l boost_thread -l boost_system && ./a.out
main end!threads id 1
chunli@Linux:~/boost$ g++ main.cpp -l boost_thread -l boost_system && ./a.out
main end!
threads id 1
chunli@Linux:~/boost$ g++ main.cpp -l boost_thread -l boost_system && ./a.out
main end!
threads id 1chunli@Linux:~/boost$ g++ main.cpp -l boost_thread -l boost_system && ./a.out
main end!
threads id 1
chunli@Linux:~/boost$ g++ main.cpp -l boost_thread -l boost_system && ./a.out
main end!
threads id 1
chunli@Linux:~/boost$
可以看出,如果沒有join的等待,結果是不可預期的.加入join,回收線程
chunli@Linux:~/boost$ cat main.cpp
#include <iostream>
#include <boost/thread.hpp>
using namespace std;
void fun1(const int &id){cout << "threads id "<<id << endl;}
int main()
{
boost::thread t1(fun1,1);
t1.join();
cout << "main end!" << endl;
return 0;
}
chunli@Linux:~/boost$ g++ main.cpp -l boost_thread -l boost_system && ./a.out
threads id 1
main end!
chunli@Linux:~/boost$ g++ main.cpp -l boost_thread -l boost_system && ./a.out
threads id 1
main end!
chunli@Linux:~/boost$ g++ main.cpp -l boost_thread -l boost_system && ./a.out
threads id 1
main end!
chunli@Linux:~/boost$ g++ main.cpp -l boost_thread -l boost_system && ./a.out
threads id 1
main end!
chunli@Linux:~/boost$線程中斷
chunli@Linux:~/boost$ cat main.cpp
#include <iostream>
#include <boost/thread.hpp>
using namespace std;
using boost::thread;
void f1(const int& id)
{
cout << "thread #" << id << ": started" << endl;
boost::system_time const timeout = boost::get_system_time()+ boost::posix_time::seconds(3);
thread::sleep(timeout);//sleep不會放棄時間片
cout << "thread #" << id << ": ended" << endl;
}
void f2(const int& id)
{
cout << "thread #" << id << ": started" << endl;
thread::yield();//預定義中斷點.主動放棄時間片
cout << "thread #" << id << ": ended" << endl;
}
void f3(const int& id)
{
cout << "thread #" << id << ": started" << endl;
boost::this_thread::interruption_point();//預定義中斷點
cout << "thread #" << id << ": ended" << endl;
}
int main()
{
thread t1(f1, 1); t1.interrupt();
thread t2(f2, 2);
thread t3(f3, 3); t3.interrupt();
t1.join();
t2.join();
t3.join();
}
chunli@Linux:~/boost$ g++ main.cpp -l boost_thread -l boost_system && ./a.out
thread #2: started
thread #1: started
thread #3: started
thread #2: ended
chunli@Linux:~/boost$ g++ main.cpp -l boost_thread -l boost_system && ./a.out
thread #1: started
thread #3: started
thread #2: started
thread #2: ended
chunli@Linux:~/boost$ g++ main.cpp -l boost_thread -l boost_system && ./a.out
thread #thread #2: started1: started
thread #3: started
thread #2: ended
chunli@Linux:~/boost$ g++ main.cpp -l boost_thread -l boost_system && ./a.out
thread #3: started
thread #1: started
thread #2: started
thread #2: ended
chunli@Linux:~/boost$ g++ main.cpp -l boost_thread -l boost_system && ./a.out
thread #2: started
thread #3: started
thread #thread #2: ended
1: started
chunli@Linux:~/boost$
只有2線程不會被打斷線程中斷2,
chunli@Linux:~/boost$ cat main.cpp
#include <iostream>
#include <boost/thread.hpp>
using namespace std;
using boost::thread;
void print(const int& id)
{
boost::this_thread::disable_interruption di;//創建一個不可被打斷的對象
cout << boost::this_thread::interruption_enabled() << endl;
cout << "thread #" << id << ": ";
//boost::this_thread::sleep(boost::posix_time::seconds(2));
boost::system_time const timeout = boost::get_system_time() + boost::posix_time::seconds(2);
thread::sleep(timeout);
for (int i = 1; i < 11; ++i)
{
cout << i << ' ';
}
cout << endl;
boost::this_thread::restore_interruption ri(di);//到這里,對象不可被打斷
cout << boost::this_thread::interruption_enabled() << endl;
//實際上,是可以被打斷
}
int main()
{
//線程還沒有運行結束,叫被打斷
thread t1(print, 1);
thread t2(print, 2);
thread t3(print, 3); t3.interrupt();
t1.join();
t2.join();
t3.join();
}
chunli@Linux:~/boost$ g++ main.cpp -l boost_thread -l boost_system && ./a.out
0
thread #1: 0
thread #3: 0
thread #2: 1 2 3 4 5 6 7 8 9 10
1
1 2 3 4 5 6 7 8 9 10
1
1 2 3 4 5 6 7 8 9 10
1
chunli@Linux:~/boost$ g++ main.cpp -l boost_thread -l boost_system && ./a.out
0
thread #1: 0
thread #2: 0
thread #3: 1 2 3 4 5 6 7 8 9 10
1
1 2 3 4 5 6 7 8 9 10
1
1 2 3 4 5 6 7 8 9 10
1
chunli@Linux:~/boost$
線程組
chunli@Linux:~/桌面/qt_pro/01/untitled$ cat main.cpp
#include <iostream>
#include <boost/thread.hpp>
using namespace std;
using boost::thread;
void f1(){ cout << "fun1 " << endl;}
void f2(){ cout << "fun2 " << endl;}
int main()
{
boost::thread_group group;
for(int i = 0;i<3;++i)
{
group.create_thread(f1);
}
group.add_thread(new boost::thread(f2));
cout<<group.size()<<endl;
group.join_all();
}
chunli@Linux:~/桌面/qt_pro/01/untitled$ g++ main.cpp -lboost_thread -lboost_system -Wall && ./a.out
fun1 4
fun1
fun2
fun1
chunli@Linux:~/桌面/qt_pro/01/untitled$ g++ main.cpp -lboost_thread -lboost_system -Wall && ./a.out
fun1
fun1
fun1
4
fun2
chunli@Linux:~/桌面/qt_pro/01/untitled$boost 線程的死鎖
chunli@Linux:~/boost$ cat main.cpp
#include <iostream>
#include <boost/thread.hpp>
using namespace std;
using boost::thread;
boost::mutex m;
void function1()
{
m.lock();
cout << "function 1 \n";
m.unlock();
}
void function2()
{
m.lock();
cout << "function 2 \n";
function1();
m.unlock();
}
int main()
{
thread t1(function1); t1.join();
thread t2(function2); t2.join();
}
chunli@Linux:~/boost$ g++ main.cpp -lboost_thread -lboost_system&& ./a.out
function 1
function 2
^C
chunli@Linux:~/boost$boost 線程遞歸鎖
chunli@Linux:~/boost$ cat main.cpp
#include <iostream>
#include <boost/thread.hpp>
using namespace std;
using boost::thread;
boost::recursive_mutex m;
void function1()
{
m.lock();
cout << "function 1 \n";
m.unlock();
}
void function2()
{
m.lock();
cout << "function 2 \n";
function1();
m.unlock();
}
int main()
{
thread t1(function1); t1.join();
thread t2(function2); t2.join();
}
chunli@Linux:~/boost$ g++ main.cpp -lboost_thread -lboost_system -lpthread && ./a.out
function 1
function 2
function 1
chunli@Linux:~/boost$線程互斥鎖,線程同步
boost::mutex m;
void function1(int id)
{
m.lock();
cout <<"thread #"<<id<<":";
for(int i=0;i<15;i++)
cout << i<<' ';
cout << endl;
m.unlock();
}
int main()
{
thread t1(function1,1); t1.join();
thread t2(function1,2); t2.join();
thread t3(function1,3); t3.join();
thread t4(function1,4); t4.join();
thread t5(function1,5); t5.join();
thread t6(function1,6); t6.join();
}
chunli@Linux:~/boost$ g++ main.cpp -lboost_thread -lboost_system -lpthread && ./a.out
thread #1:0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
thread #2:0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
thread #3:0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
thread #4:0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
thread #5:0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
thread #6:0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
chunli@Linux:~/boost$unique_lock 鎖,離開作用域自動釋放
chunli@Linux:~/boost$ cat main.cpp
#include <iostream>
#include <list>
#include <boost/thread.hpp>
using namespace std;
using boost::thread;
boost::mutex m;
int k = 0;
void decrement()
{
boost::unique_lock<boost::mutex> lock(m);
for(int i = 0;i<=100;++i)
{
k-=i;
}
cout << "after decrement k="<<k << endl;
}
void increment()
{
boost::unique_lock<boost::mutex> lock(m);
for(int i = 0;i<=100;++i)
{
k+=i;
}
cout << "after increment k="<<k << endl;
}
int main()
{
boost::thread t1(increment); t1.join();
boost::thread t2(decrement); t2.join();
}
chunli@Linux:~/boost$ g++ main.cpp -lboost_thread -lboost_system -lpthread && ./a.out
after increment k=5050
after decrement k=0
chunli@Linux:~/boost$unique_lock 鎖 示例 2,可以顯式的釋放鎖
chunli@Linux:~/boost$ cat main.cpp
#include <iostream>
#include <vector>
#include <boost/thread.hpp>
using namespace std;
using boost::thread;
boost::mutex m;
void updateString()
{
boost::unique_lock<boost::mutex> lock(m);//lock
lock.unlock();//unlock
lock.lock();
}
int main()
{
thread t1(updateString); t1.join();
thread t2(updateString); t2.join();
}
chunli@Linux:~/boost$ g++ main.cpp -lboost_thread -lboost_system -lpthread && ./a.out
chunli@Linux:~/boost$boost 1次初始化
chunli@Linux:~/boost$ cat main.cpp
#include <iostream>
#include <boost/thread.hpp>
using namespace std;
using boost::thread;
boost::once_flag once = BOOST_ONCE_INIT; // 注意這個操作不要遺漏了
void func() {
cout << "Will be called but one time!" << endl;
}
void threadFunc() {
// func();
boost::call_once(&func, once);
}
int main() {
boost::thread_group threads;
for (int i = 0; i < 5; ++i)
threads.create_thread(&threadFunc);
threads.join_all();
}
chunli@Linux:~/boost$ g++ main.cpp -lboost_thread -lboost_system && ./a.out
Will be called but one time!
chunli@Linux:~/boost$boost 條件變量
chunli@Linux:~/boost$ cat main.cpp
#include <iostream>
#include <boost/thread.hpp>
using namespace std;
using boost::thread;
boost::condition_variable cond; // 關聯多個線程的條件變量
boost::mutex m; // 保護共享資源 k 的互斥體
int k = 0; // 共享資源
void f1(const int& id)
{
boost::unique_lock<boost::mutex> lock(m);
while (k < 5)
{
cout << "thread #" << id << ": k < 5, waiting ..." << endl;
cond.wait(lock); // #1
}
cout << "thread #" << id << ": now k >= 5, printing ..." << endl;
}
void f2(const int& id)
{
boost::unique_lock<boost::mutex> lock(m);
cout << "thread #" << id << ": k will be changed ..." << endl;
k += 5;
cond.notify_all(); // #2 不需lock
}
int main() {
// 如果f2()中是 cond.notify_one()，結果？
boost::thread t1(f1, 1);
boost::thread t2(f1, 2);
boost::thread t3(f2, 100);
t1.join();
t2.join();
t3.join();
}
chunli@Linux:~/boost$ g++ main.cpp -lboost_thread -lboost_system && ./a.out
thread #1: k < 5, waiting ...
thread #2: k < 5, waiting ...
thread #100: k will be changed ...
thread #1: now k >= 5, printing ...
thread #2: now k >= 5, printing ...
chunli@Linux:~/boost$boost 線程鎖,一個賬戶往另外一個賬戶轉錢案例
chunli@Linux:~/boost$ cat main.cpp
#include <iostream>
#include <boost/thread.hpp>
using namespace std;
using boost::thread;
class Account {
boost::mutex m;
double balance;
public:
Account() :
balance() {
}
Account(const double& bal) :
balance(bal) {
}
double getBalance() const {
return balance;
}
friend void transfer(Account& from, Account& to, double amount);
};
//// version 3: OK （使用lock() 和 unique_lock）
//void transfer(Account& from, Account& to, double amount) {
// boost::lock(from.m, to.m);
// boost::unique_lock<boost::mutex> lockFrom(from.m, boost::adopt_lock);
// boost::unique_lock<boost::mutex> lockTo(to.m, boost::adopt_lock);
//
// from.balance -= amount;
// to.balance += amount;
//}
// version 2: OK （使用lock() 和 lock_guard）
void transfer(Account& from, Account& to, double amount) {
boost::lock(from.m, to.m);
boost::lock_guard<boost::mutex> lockFrom(from.m, boost::adopt_lock);
boost::this_thread::sleep(boost::posix_time::seconds(1));
boost::lock_guard<boost::mutex> lockTo(to.m, boost::adopt_lock);
from.balance -= amount;
to.balance += amount;
}
// version 1: 可能造成死鎖
//void transfer(Account& from, Account& to, double amount) {
// boost::lock_guard<boost::mutex> lockFrom(from.m); // #1
// boost::this_thread::sleep(boost::posix_time::seconds(1));
// boost::lock_guard<boost::mutex> lockTo(to.m); // #2
// from.balance -= amount;
// to.balance += amount;
//}
int main() {
Account a1(1200.00);
Account a2(300.00);
boost::thread t1(transfer, boost::ref(a1), boost::ref(a2), 134.85);
boost::thread t2(transfer, boost::ref(a2), boost::ref(a1), 100.30);
t1.join();
t2.join();
cout << "Balance of a1: " << a1.getBalance() << endl;
cout << "Balance of a2: " << a2.getBalance() << endl;
}
chunli@Linux:~/boost$ g++ main.cpp -lboost_thread -lboost_system -lpthread && ./a.out
Balance of a1: 1165.45
Balance of a2: 334.55
chunli@Linux:~/boost$boost upgrade_lock
chunli@Linux:~/boost$ cat main.cpp
#include <iostream>
#include <boost/thread.hpp>
using namespace std;
using boost::thread;
boost::shared_mutex m;
int k = 1;
void f(int id) {
boost::upgrade_lock<boost::shared_mutex> lock(m);
cout << "thread #" << id << ": " << k << endl;
if (k < 6) {
// boost::unique_lock<boost::shared_mutex> lock2(boost::move(lock)); // alternate:
boost::upgrade_to_unique_lock<boost::shared_mutex> lock2(lock);
k += 3;
}
}
int main() {
boost::thread t1(f, 1);
boost::thread t2(f, 2);
boost::thread t3(f, 3);
t1.join();
t2.join();
t3.join();
}
chunli@Linux:~/boost$ g++ main.cpp -lboost_thread -lboost_system -lpthread && ./a.out
thread #2: 1
thread #1: 4
thread #3: 7
chunli@Linux:~/boost$以上是“C++中Boost多線程、線程同步的示例分析”這篇文章的所有內容，感謝各位的閱讀！相信大家都有了一定的了解，希望分享的內容對大家有所幫助，如果還想學習更多知識，歡迎關注億速云行業資訊頻道！
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