Race condition when using std::atomic with custom data type in C++17
I've spent hours debugging this and I'm following best practices but I tried several approaches but none seem to work. I'm currently working with a race condition scenario while trying to use `std::atomic` with a custom data type in my C++17 project. I've defined a simple struct with two integers, and I intended to use `std::atomic` to ensure thread safety when modifying its values from multiple threads. However, when I run the code, I encounter inconsistent results and occasional crashes. Here's the relevant code snippet: ```cpp #include <iostream> #include <atomic> #include <thread> struct MyData { int a; int b; }; std::atomic<MyData> atomicData; void updateData(int x, int y) { MyData newData = {x, y}; atomicData.store(newData); } int main() { atomicData.store({0, 0}); std::thread t1(updateData, 1, 2); std::thread t2(updateData, 3, 4); t1.join(); t2.join(); MyData result = atomicData.load(); std::cout << "Result: " << result.a << ", " << result.b << std::endl; return 0; } ``` I'm using GCC 9.3.0 on Ubuntu 20.04. When I execute this code, I'm getting unexpected results for `result.a` and `result.b`, and sometimes even a segmentation fault. I’ve tried ensuring the `MyData` struct is trivially copyable, but it didn't resolve the scenario. Additionally, I attempted to wrap the accesses to `atomicData` in a mutex, but that seems to defeat the purpose of using `std::atomic`. How can I correctly use `std::atomic` with a custom data type like this, or am I missing something in my implementation? What's the best practice here? What's the best practice here? Any advice would be much appreciated.