Re: Atomic caching of smart pointers

On 15.09.2024 23:15, Chris M. Thomasson wrote:

On 9/15/2024 11:54 AM, Paavo Helde wrote:
[...]

So, what do you think? Should I just use std::atomic<std::shared_ptr> instead? Any other suggestions? Did I get the memory order parameters right in compare_exchange_weak()?

 Keep in mind that you need to make sure that std::atomic<std::shared_ptr> is actually lock-free...
 Make sure to investigate is_always_lock_free on your various arch's:
 https://en.cppreference.com/w/cpp/atomic/atomic/is_always_lock_free

I already checked this, it is returning false at least on one of my target platforms (Visual Studio 2022, Windows x86_64). IIRC Bonita claimed this might be a false negative though.
Meanwhile I think I found a bug in my posted code, I should probably use compare_exchange_strong() instead of compare_exchange_weak(). I somehow thought the latter would err on the safe side, but it does not. In my test harness there seems to be no difference.