目录

1.多线程

#include <iostream>
// 必须的头文件
#include <pthread.h>using namespace std;#define NUM_THREADS 5// 线程的运行函数
void* say_hello(void* args)
{cout << "Hello Runoob！" << endl;return 0;
}int main()
{// 定义线程的 id 变量，多个变量使用数组pthread_t tids[NUM_THREADS];for(int i = 0; i < NUM_THREADS; ++i){//参数依次是：创建的线程id，线程参数，调用的函数，传入的函数参数int ret = pthread_create(&tids[i], NULL, say_hello, NULL);if (ret != 0){cout << "pthread_create error: error_code=" << ret << endl;}}//等各个线程退出后，进程才结束，否则进程强制结束了，线程可能还没反应过来；pthread_exit(NULL);
}

#include <iostream>
#include <cstdlib>
#include <pthread.h>using namespace std;#define NUM_THREADS     5struct thread_data{int  thread_id;char *message;
};void *PrintHello(void *threadarg)
{struct thread_data *my_data;my_data = (struct thread_data *) threadarg;cout << "Thread ID : " << my_data->thread_id ;cout << " Message : " << my_data->message << endl;pthread_exit(NULL);
}int main ()
{pthread_t threads[NUM_THREADS];struct thread_data td[NUM_THREADS];int rc;int i;for( i=0; i < NUM_THREADS; i++ ){cout <<"main() : creating thread, " << i << endl;td[i].thread_id = i;td[i].message = (char*)"This is message";rc = pthread_create(&threads[i], NULL,PrintHello, (void *)&td[i]);if (rc){cout << "Error:unable to create thread," << rc << endl;exit(-1);}}pthread_exit(NULL);
}

#include <iostream>
#include <cstdlib>
#include <pthread.h>
#include <unistd.h>using namespace std;#define NUM_THREADS     5void *wait(void *t)
{int i;long tid;tid = (long)t;sleep(1);cout << "Sleeping in thread " << endl;cout << "Thread with id : " << tid << "  ...exiting " << endl;pthread_exit(NULL);
}int main ()
{int rc;int i;pthread_t threads[NUM_THREADS];pthread_attr_t attr;void *status;// 初始化并设置线程为可连接的（joinable）pthread_attr_init(&attr);pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);for( i=0; i < NUM_THREADS; i++ ){cout << "main() : creating thread, " << i << endl;rc = pthread_create(&threads[i], NULL, wait, (void *)&i );if (rc){cout << "Error:unable to create thread," << rc << endl;exit(-1);}}// 删除属性，并等待其他线程pthread_attr_destroy(&attr);for( i=0; i < NUM_THREADS; i++ ){rc = pthread_join(threads[i], &status);if (rc){cout << "Error:unable to join," << rc << endl;exit(-1);}cout << "Main: completed thread id :" << i ;cout << "  exiting with status :" << status << endl;}cout << "Main: program exiting." << endl;pthread_exit(NULL);
}

当上面的代码被编译和执行时，它会产生下列结果：
main() : creating thread, 0
main() : creating thread, 1
main() : creating thread, 2
main() : creating thread, 3
main() : creating thread, 4
Sleeping in thread
Thread with id : 4 …exiting
Sleeping in thread
Thread with id : 3 …exiting
Sleeping in thread
Thread with id : 2 …exiting
Sleeping in thread
Thread with id : 1 …exiting
Sleeping in thread
Thread with id : 0 …exiting
Main: completed thread id :0 exiting with status :0
Main: completed thread id :1 exiting with status :0
Main: completed thread id :2 exiting with status :0
Main: completed thread id :3 exiting with status :0
Main: completed thread id :4 exiting with status :0
Main: program exiting.

#include <iostream>#include <thread>std::thread::id main_thread_id = std::this_thread::get_id();void hello()  
{std::cout << "Hello Concurrent World\n";if (main_thread_id == std::this_thread::get_id())std::cout << "This is the main thread.\n";elsestd::cout << "This is not the main thread.\n";
}void pause_thread(int n) {std::this_thread::sleep_for(std::chrono::seconds(n));std::cout << "pause of " << n << " seconds ended\n";
}int main() {std::thread t(hello);std::cout << t.hardware_concurrency() << std::endl;//可以并发执行多少个(不准确)std::cout << "native_handle " << t.native_handle() << std::endl;//可以并发执行多少个(不准确)t.join();std::thread a(hello);a.detach();std::thread threads[5];                         // 默认构造线程std::cout << "Spawning 5 threads...\n";for (int i = 0; i < 5; ++i)threads[i] = std::thread(pause_thread, i + 1);   // move-assign threadsstd::cout << "Done spawning threads. Now waiting for them to join:\n";for (auto &thread : threads)thread.join();std::cout << "All threads joined!\n";
}

2.web编程