Multithreading in C++

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Multithreading allows a program to execute multiple threads concurrently, improving performance and responsiveness.

C++ multithreading support is provided through:

#include 

What is a Thread?

A thread is the smallest unit of execution within a process.

Creating a Thread

Using a Function

#include 
#include 
using namespace std;

void display() {
    cout << "Hello from thread";
}

int main() {
    thread t(display);
    t.join();
    return 0;
}

join() and detach()

• join() → waits for the thread to finish

• detach() → runs thread independently

t.join();
t.detach();

Passing Arguments to Threads

void show(int x) {
    cout << x>thread t(show, 10);

Lambda with Thread

thread t([]() {
    cout << "Lambda thread";
});

Thread Synchronization

Used to avoid data inconsistency.

Mutex (std::mutex)

#include 

mutex m;

void print() {
    m.lock();
    cout << "Critical section";
    m.unlock();
}

lock_guard (Recommended)

void print() {
    lock_guard lock(m);
    cout << "Safe access";
}

Race Condition

Occurs when multiple threads access shared data simultaneously.

Solution:

• Mutex

• Atomic operations

Atomic Variables

#include 

atomic<int> count = 0;
count++;

Condition Variables

Used for thread communication.

#include 

Example: Multiple Threads

thread t1(func1);
thread t2(func2);

t1.join();
t2.join();

Advantages of Multithreading

• Faster execution

• Better CPU utilization

• Responsive applications

Challenges

• Deadlocks

• Race conditions

• Debugging complexity

Key Points

• Threads run concurrently

• Use synchronization tools

• Avoid shared data issues

• Use join() to prevent crashes

Conclusion

Multithreading in C++ enables high-performance and responsive applications when used carefully with proper synchronization.