👀 Views: 290 💬 Answers: 1 📅 Created: 2025-06-13

c++ multithreading shared-ptr cpp

I'm working on a personal project and I can't seem to get I'm working on a personal project and I'm working with a double free behavior when using `std::shared_ptr` to share a resource between multiple threads in my application... I am using C++17 and have the following setup: ```cpp #include <iostream> #include <memory> #include <thread> #include <vector> struct Data { int value; }; void threadFunction(std::shared_ptr<Data> dataPtr) { std::cout << "Value: " << dataPtr->value << std::endl; } int main() { std::shared_ptr<Data> sharedData = std::make_shared<Data>(); sharedData->value = 42; std::vector<std::thread> threads; for (int i = 0; i < 5; ++i) { threads.emplace_back(threadFunction, sharedData); } for (auto& t : threads) { t.join(); } // Intentionally resetting to see the effect sharedData.reset(); return 0; } ``` When I run this code, sometimes I get a segmentation fault, and when debugging, I see messages indicating a double free. I have verified that there are no other explicit deletions happening. I suspect that the scenario arises because I reset the `sharedData` while threads may still be using it, but I'm not exactly sure how to address this properly. I've considered using `std::atomic` or managing the lifetime of the shared pointer more carefully, perhaps by using a mutex, but I’m not clear on the best approach. Has anyone dealt with this kind of scenario, and what would be the best practices for safely sharing `std::shared_ptr` across threads in a C++ context? I'm working on a application that needs to handle this. What am I doing wrong? For reference, this is a production desktop app. Any suggestions would be helpful. Is there a simpler solution I'm overlooking?