查阅了相关资料,调用exit函数会直接将进程返回给操作系统,不论是在进程中主线程还是子线程中调用,都会直接将控制权返回给操作系统。

代码1:在主线程中调用exit退出。

#include <iostream>#include <thread>using namespace std;void thread_fun(){    cout<<"thread_fun run"<<endl;    //exit(0);}void atexit_fun1(){    cout<<"atexit fun1 run"<<endl;}void atexit_fun2(){    cout<<"atexit fun2 run"<<endl;}int main(){    /*    thread thread_obj(thread_fun);    thread_obj.join();    */    thread thread_obj(thread_fun);    thread_obj.join();    cout<<"main run"<<endl;    atexit(atexit_fun1);    atexit(atexit_fun2);    exit(0);}

输出如下:

代码2:在子线程中调用exit函数

#include <iostream>#include <thread>using namespace std;void thread_fun(){    cout<<"thread_fun run"<<endl;    exit(0);}void atexit_fun1(){    cout<<"atexit fun1 run"<<endl;}void atexit_fun2(){    cout<<"atexit fun2 run"<<endl;}int main(){    /*    thread thread_obj(thread_fun);    thread_obj.join();    */    thread thread_obj(thread_fun);    thread_obj.join();    cout<<"main run"<<endl;    atexit(atexit_fun1);    atexit(atexit_fun2);    exit(0);}

输出如下:

可见在子线程中调用exit函数后,整个程序全部退出了,包括子线程。