dup学习

#include <cstdio>#include <thread>#include <chrono>#include <mutex>#include <unistd.h>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>using namespace std;using namespace std::chrono;int main(int argc,char* argv[]){int fd,fd_dup;int index=0;mutex mut;fd_dup=dup(STDOUT_FILENO);fd=dup(STDOUT_FILENO);thread dup_thread([&]()    //must be reference{while(true){this_thread::sleep_for(milliseconds(700)); //sleep for 700 mslock_guard<mutex> guard(mut);if(index<20){printf("dup_thread: index= %d\n",index);   //output++index;}elsebreak;}close(fd_dup);return ;});while(true){this_thread::sleep_for(seconds(1));lock_guard<mutex> guard(mut);if(index<20){printf("main_thread: index= %d\n",index);++index;}elsebreak;}dup_thread.join();close(fd);return 0;}

g++ -std=c++11 -pthread -g -Wall test_dup.cpp./a.out