Example of std::shared_lock

Methods Associated with std::shared_mutex

C++

// C++ program to illustrate the use of shared_mutex 
#include <iostream> 
#include <shared_mutex> 
#include <mutex> 
#include <thread> 
using namespace std; 
  
// creating a shared_mutex object 
shared_mutex mutx; 
int shared_data = 11; 
  
// callable with shared lock 
void readData() { 
    shared_lock<shared_mutex> lock(mutx); 
    cout << "Thread " << this_thread::get_id() << ": ";  
    cout << shared_data << endl; 
} 
  
// callable with unique_lock 
void writeData(int n) { 
    unique_lock<shared_mutex> lock(mutx); 
    shared_data = n; 
    cout << "Thread" << this_thread::get_id() << ": \n"; 
} 
  
// driver code 
int main() 
{ 
    thread t1(readData); 
    thread t2(writeData, 128); 
    thread t3(writeData, 10); 
    thread t4 (readData); 
      
    t1.join(); 
    t2.join(); 
    t3.join(); 
    t4.join(); 
    return 0; 
}

Output

Read Thread 140122977658432: 11
Write Thread 140122960873024
Write Thread 140122969265728
Read Thread 140122952480320: 128

std::shared_mutex in C++

In C++, std::mutex is a mechanism that locks access to the shared resource when some other thread is working on it so that errors such as race conditions can be avoided and threads can be synchronized. But in some cases, several threads need to read the data from shared resources at the same time. Here, the std::shared_mutex comes into play. In this article, we will discuss the std::shared_mutex, its associated methods, and how it is different from the std::mutex in C++.

Prerequisite: C++ Multithreading, std::mutex in C++.

Example of std::shared_lock

C++

std::shared_mutex in C++

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