C++11 Multi-Threading 03

First, correct the previous error: The thread has run before the join () has been called.

#include <iostream>#include<thread>#include<mutex>voidShared_print (std::stringName,intnum) {Std::cout<<name<<":"<<num<<Std::endl;}voidThread_fun () { for(inti =0; i>- -; i--) {Shared_print ("Child Threads", i); }}intMain () {Std::thread T (thread_fun);  for(intI=0;i< -; i++) {Shared_print ("Main Thread", i); }//T.join ();    return 0;}

The following still add the join, the current program output is very messy

#include <iostream>#include<thread>#include<mutex>voidShared_print (std::stringName,intnum) {Std::cout<<name<<":"<<num<<Std::endl;}voidThread_fun () { for(inti =0; i>- -; i--) {Shared_print ("Child Threads", i); }}intMain () {Std::thread T (thread_fun);  for(intI=0;i< -; i++) {Shared_print ("Main Thread", i);    } t.join (); return 0;}

Use basic mutex to solve resource competition, see output not messy

#include <iostream>#include<thread>#include<mutex>Std::mutex mu;voidShared_print (std::stringName,intnum) {mu.Lock(); Std::cout<<name<<":"<<num<<std::endl;//Cons: If a thread crashes here, it can never be unlock.Mu.unlock ();}voidThread_fun () { for(inti =0; i>- -; i--) {Shared_print ("Child Threads", i); }}intMain () {Std::thread T (thread_fun);  for(intI=0;i< -; i++) {Shared_print ("Main Thread", i);    } t.join (); return 0;}

Improved: auto-release mu

#include <iostream>#include<thread>#include<mutex>Std::mutex mu;voidShared_print (std::stringName,intnum) {    //Advantage: When the guard is deconstructed, MU will be released automatically, not afraid of the following sentence exception//Cons: Cout is a global object, not fully protected, other places can still be used in lock-up situationsStd::lock_guard<std::mutex>Guard (MU); Std::cout<<name<<":"<<num<<Std::endl;}voidThread_fun () { for(inti =0; i>- -; i--) {Shared_print ("Child Threads", i); }}intMain () {Std::thread T (thread_fun);  for(intI=0;i< -; i++) {Shared_print ("Main Thread", i);    } t.join (); return 0;}

Continue optimization: Remove the disadvantage of the previous program

#include <iostream>#include<thread>#include<mutex>#include<fstream>classloffile{ Public: Loffile () {F.open ("Log.txt"); }    voidShared_print (std::stringName,intnum) {Std::lock_guard<std::mutex>Locker (M_mutex); F<<name<<": "<<num<<Std::endl; }Private: Std::mutex M_mutex; Std::ofstream F;};voidThread_fun (loffile&log) {     for(inti =0; i>- -; i--) {Log.shared_print ("Child Threads", i); }}intMain () {loffile log; Std::thread T (thread_fun,std::ref(log));  for(intI=0;i< -; i++) {Log.shared_print ("Main Thread", i);    } t.join (); return 0;}

C++11 Multi-Threading 03