Disconnect issue

[tobbe303]

There is a disconnect issue in the examples that puzzles me. The sigint_handler and the subsequent disconnection handler are invoked upon sending the interrupt signal, but the main function does not terminate.

Adding a sleep(1) inside the "while (not should_exit);" loop appears to solve the termination issue, but is there possibly a disconnect/threading issue at play here?

Thank you for a nice Redis client!

[Cylix]

On which example: redis_client, redis_subscriber or both of them?

[tobbe303]

Both of them. Using g++ (Ubuntu 4.8.4-2ubuntu1~14.04) 4.8.4.

[Cylix]

Mmh, if it was only in the redis_subscriber, the problem may have been caused by a compiler optimization because the should_exit variable is not marked as volatile (unlike in the redis_client example): because the loop is empty, the compiler sometimes optimizes the loop to a simple while (true) without the need to access the value of should_exit.

But if it is on both examples, then I will need to check my implementation.

Does it happen every time?

[tobbe303]

Yes, it happens every time on my machine in both examples. I've also tried volatile etc. but no avail so far.

I also notice the main thread appears to get suspended upon disconnection. If I output the should_exit value to stderr inside the loop I notice the output stops.

[Cylix]

Ok, I finally managed to reproduce the issue. It never happens on my mac, but I got it sometimes (maybe 10% of the time) on a debian VM.

I've localised the issue in the tcp client.

It's a similar problem that the one reported in #3: sometimes the conditional variable is locked after having been notified by the other thread.

I should patch it this evening if I have the time.

[Cylix]

I've added atomic variables to avoid waiting if conditional variable has already been notified.
After this modification, I'm not able to reproduce the issue on my computer.

Could you please tell me if everything is ok now? Or if the problem is still there for you?

[tobbe303]

The redis_client example is working now, but the redis_subscriber example still hangs on interrupt. However, making the should_exit variable in this example volatile std::atomic_bool (which is the type the redis_client uses) seems to do the trick!

Thanks!

[Cylix]

Oh, yes, I've forgotten to commit this! This is now done, I close the issue.

Thank you again for your help :)