日常随笔——C++中获取当前线程ID

一般有四种
参考链接：Linux下获取线程ID

#include <pthread.h>
#include <thread>
#include <iostream>
#include <unistd.h>
#include <stdio.h>

#include <sys/syscall.h>  
#define gettid() syscall(__NR_gettid)
#define NUM_THREADS 5
using namespace std;

// 线程的运行函数
mutex mtx;

void fun(){
    std::unique_lock<std::mutex> lck(mtx);
    cout<<"This in fun()"<<endl;
    cout<<"process id: "<<getpid()<<endl;
    cout<<"kernel id: "<<gettid()<<endl;
    cout<<"std thread id: "<< std::this_thread::get_id()<<endl;
    cout<<"pthread id:"<< pthread_self()<<endl;
}

void* say_hello(void* args)
{
    cout<<"process id: "<<getpid()<<endl;
    cout<<"kernel id: "<<gettid()<<endl;
    cout<<"std thread id: "<< std::this_thread::get_id()<<endl;
    cout<<"pthread id:"<< pthread_self()<<endl;
    fun();
    return 0;
}

int main() {
    //int t =
    // 定义线程的 id 变量，多个变量使用数组;

    cout<<"process id: "<<getpid()<<endl;   // 获取的是进程识别码，不唯一
    cout<<"kernel id: "<<gettid()<<endl;    // 从内核获取线程id，唯一，使用前需要进行封装
    cout<<"std thread id: "<< std::this_thread::get_id()<<endl; // thread类封装得到的id，每个线程唯一
    cout<<"pthread id:"<< pthread_self()<<endl;  // 同thread类


    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);

    return 0;
}