Hi Sebastian, Thanks for your reply. You solution will definitely work for my case.
From a defensive programming point of view, it would still be nice to automatically clean all the resource during dll unloading, and it would be useful if user unloads the dll but doesn't shut down the process. But I'll leave this to the boost developers.
Regards,
Bo
On 3 October 2013 21:25, Sebastian Redl
On Oct 1, 2013, at 10:22, Bo Peng wrote:
I have a Windows DLL, which uses boost::asio::deadline_timer. I found
that
deadline_timer::async_wait creates a timer thread as a private member of io_service. This thread won't be shut down even if all the timers are cancelled. In the destructor of io_service, 'join' will be called on the thread. In some exceptional situation, users might exit their main function before destructs the io_service inside my DLL, so the destructor is called during the unloading of the DLL, which hangs their process.
boost::shared_ptr<Action> action;
In my opinion, the solution here is to not destroy this object automatically on unload. Turn it into a raw pointer. In the exceptional situation, you'll leak the object and the I/O service and the thread, but since the user is about to exit the main function (at least from your description), the process will terminate anyway.
You could add a line to DllMain's PROCESS_DETACH that checks whether the pointer is non-null and prints a warning message to the debug log if you want the user to have a chance to know about this happening.
Sebastian
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