C++11 Multithreading Tutorial PDF | Learn Concepts of Multithreading in C++ Free Online with Examples

In the previous article, we have discussed about C++ Programming Tutorial for Beginners. Let us learn About Multithreading Tutorial PDF in C++ Program.

Excited to learn more about Multithreading in C++? Viewing BTech Geeks best & free online C++11 Multithreading Tutorial can be your savior in providing better learnings and great knowledge. The support of multithreading was initiated in C++11. Earlier, POSIX threads or p threads library in C is used to call threads.

Get into this ultimate online tutorial of C++11 Multi-thread and check out the information that you require like definitions, functions, methods, working of <thread>, etc. with Examples.

Concepts in C++11 Multithreading Tutorial

Firstly, before understanding the basics about C++11 Multi-thread, you guys should aware of the topics included in this C++11 Multithreading Tutorial for a quick reference. Just take a glance at the direct links furnished below and get in-depth knowledge regarding std::thread in C++.

  • Part 1: Three Ways to Create Threads
  • Part 2: Joining and Detaching Threads
  • Part 3: Passing Arguments to Threads
  • Part 4: Sharing Data & Race Conditions
  • Part 5: Fixing Race Conditions using mutex
  • Part 6: Need of Event Handling
  • Part 7: Condition Variables
  • Part 8: std::future and std::promise
  • Part 9: std::async Tutorial & Example
  • Part 10: std::packaged_task<> Tutorial

C++11 Threads FAQ Topics List

  • C++11: Start thread by the member function
  • C++11: How to put a thread to sleep
  • C++11: How to get a Thread ID?
  • C++11: Vector of Thread Objects
  • C++11: std::thread as a member variable in class
  • C++11: How to Stop a Thread

After going through the above links, you’ll definitely retain all core C++11 multithreading concepts. But now, we will be discussing some fundamentals and major information like What is Thread, Uses of Multithreading, Different ways of launching threads, and most importantly quiz and interview questions on Multithreading in C++11.

Do Check Related C++ Tutorials:

What is Thread?

A thread is a Class that represents individual threads of execution. Every single thread shares memory, file descriptors, and diverse system resources. Actually, earlier in Linux, all thread functions are stated in <pthread.h> header file but it is unavailable in standard C++ programming.

What is Multithreading in C++?

A specialized form of multitasking that accepts your computer to work two or more programs concurrently is known as Multithreading. Basically, multitasking is divided into two types. They are process-based and thread-based.

In C++, a Multi-threaded program includes two or more parts that execute concurrently. All limitations that are covered in the prior threads library in C are defeated with this std::thread. Related Classes and Functions of thread are defined in the thread header file.

Working of <thread> in C++11

std::thread is the thread class that provides a single thread in C++. For working of thread, we have to create a new thread object & then the executing code is passed and it will be called (ie., a callable object) into the constructor of the object. After creating an object a new thread is initiated that will execute the code stated in callable.

Syntax:

#include<thread>
std::thread thread_object(callable)

C++ Thread Class Example

The below-illustrated example is on how we can create a simple HelloWorld program with threads:

#include <iostream>
#include <thread>
 
     //This function will be called from a thread
 
      void call_from_thread() 
      {
          std::cout << "Hello, World" << std::endl;
      }
 
    int main() 
   {
      //Launch a thread
     std::thread t1(call_from_thread);

        //Join the thread with the main thread
       t1.join();
       return 0;
    }

Different Ways of Creating a Thread in C++

Basically, there are four ways of launching a thread in C++ and they are as such:

  • Launching a thread using a function pointer
  • Launching a thread using a function object
  • Launching a thread using a lambda
  • Launching a thread using a member function

From the below multithreading in C++ program, you will observe creating the three threads from the main function by using the three main callable objects that are listed above:

// CPP program to demonstrate multithreading
// using three different callables.
#include <iostream>
#include <thread>
using namespace std;
  
// A dummy function
void foo(int Z)
{
    for (int i = 0; i < Z; i++) {
        cout << "Thread using function"
               " pointer as callable\n";
    }
}
  
// A callable object
class thread_obj {
public:
    void operator()(int x)
    {
        for (int i = 0; i < x; i++)
            cout << "Thread using function"
                  " object as  callable\n";
    }
};
  
int main()
{
    cout << "Threads 1 and 2 and 3 "
         "operating independently" << endl;
  
    // This thread is launched by using 
    // function pointer as callable
    thread th1(foo, 3);
  
    // This thread is launched by using
    // function object as callable
    thread th2(thread_obj(), 3);
  
    // Define a Lambda Expression
    auto f = [](int x) {
        for (int i = 0; i < x; i++)
            cout << "Thread using lambda"
             " expression as callable\n";
    };
  
    // This thread is launched by using 
    // lamda expression as callable
    thread th3(f, 3);
  
    // Wait for the threads to finish
    // Wait for thread t1 to finish
    th1.join();
  
    // Wait for thread t2 to finish
    th2.join();
  
    // Wait for thread t3 to finish
    th3.join();
  
    return 0;
}

Result:

Threads 1 and 2 and 3 operating independently 
Thread using function pointer as callable 
Thread using lambda expression as callable 
Thread using function pointer as callable 
Thread using lambda expression as callable 
Thread using function object as callable 
Thread using lambda expression as callable 
Thread using function pointer as callable 
Thread using function object as callable 
Thread using function object as callable

Uses of Multi-threading in C++11

A multithreading environment lets you drive many activities concurrently, where diverse threads are responsible for diverse activities. You can explore different uses of multi-threading in C++ while learning or coding on your own. But for now, we are going to see some of them below. They are as follows:

  • Better resource utilization.
  • More responsive programs.
  • Simpler program design.

Top 10 C++11 Multithreading Interview Questions List

The list of 10 best and most common interview questions on multithreading in C++11 is prevailing here for all freshers who are preparing & appearing for the software jobs in the C++ Programming language.

  1. What is multithreading?
  2. What are the ways to create a thread in C++?
  3. Brief me about the available models in Multithreading?
  4. What is C++11 thread local storage (thread_local)?
  5. What is the difference between a thread and a process?
  6. Name the design pattern for the thread?
  7. What are the 6 synchronizations primitive available in Multithreading?
  8. What is a thread pool?
  9. What is thread starvation?
  10. How can you create background tasks with C++11 threads?