Handling Exceptions in Multithreaded C++ Programs

How do I handle exceptions in a multithreaded C++ program?

Handling exceptions in a multithreaded C++ program can be challenging because exceptions thrown in one thread do not propagate to other threads.

Each thread operates independently, so exception handling must be managed within the thread itself. Here's how you can handle exceptions in a multithreaded environment:

  1. Catch exceptions within each thread: Ensure that each thread catches exceptions to avoid unhandled exceptions that could terminate the thread or the entire program.
  2. Communicate exceptions to the main thread: Use mechanisms such as std::promise and std::future to pass exceptions from worker threads to the main thread.

Here's an example to illustrate this:

#include <future>
#include <iostream>
#include <stdexcept>
#include <thread>

void Task(std::promise<void>&& promise) {
  try {
    // Simulate an error
    throw std::runtime_error("Something went wrong!");
  } catch (...) {
    promise.set_exception(std::current_exception());
  }
}

int main() {
  std::promise<void> promise;
  std::future<void> future = promise.get_future();
  std::thread t(Task, std::move(promise));

  try {
    future.get();
  } catch (const std::exception& e) {
    std::cout << "Exception caught: " << e.what();
  }

  t.join();
}
Exception caught: Something went wrong!

In this example, the Task function throws an exception, which is caught and set on the std::promise. The main thread retrieves this exception through the std::future and handles it.

Key points to remember:

  • Always catch exceptions within each thread to prevent unexpected termination.
  • Use std::promise and std::future for safe exception communication between threads.
  • Consider using a thread pool to manage multiple threads and handle exceptions more effectively.

This approach ensures that exceptions in worker threads are properly handled and can be communicated back to the main thread or a central exception handler.

Parallel Algorithm Execution

Multithreading in C++ standard library algorithms using execution policies

Questions & Answers

Answers are generated by AI models and may not have been reviewed. Be mindful when running any code on your device.

Concurrency vs Parallelism in C++
What is the difference between concurrency and parallelism in C++?
Using Execution Policies with Custom Algorithms in C++
Can execution policies be used with custom algorithms or only standard library algorithms?
Controlling the Number of Threads Used by Execution Policies in C++
How do I control the number of threads used by std::execution::par?
Difference Between std::execution::par and std::execution::par_unseq
How does std::execution::par_unseq differ from std::execution::par?
The Role of Thread Pools in Parallel Execution
What is the role of thread pools in parallel execution?
Parallel Execution and Asynchronous Programming in C++
How does parallel execution interact with asynchronous programming in C++?
Or Ask your Own Question
Get an immediate answer to your specific question using our AI assistant