Using flashmq_add_task from the plugin

[slavslavov]

Will the task be executed in the context of the calling thread? Let's say in flashmq_plugin_init I call flashmq_add_task to run a task a few seconds later and I capture the thread_data. When I get my task called back will it be from the same thread I called flashmq_add_task and will thread_data be valid at this point?

And if I am running FlashMQ on a 4 core CPU and having 4 threads, I guess my task will be executed 4 times - once per each thread.

[wiebeytec]

Yes, the task is placed in the queued tasks list of the current thread's event loop. You can capture thread_data and the same thread will perform the task. You can be sure the thead_data is not simultanously accessed elsewhere.

And yes, if you have 4 threads, you get four tasks, which you can influence by some kind of static/atomic memory counter, if you want.

See here BTW for what flashmq_add_task does.

Side note:

and will thread_data be valid at this point?

By 'valid', you imply that accessing thread_data of another thread is invalid. It's fine actually, if properly mutexed, but there should be no reason to do it. The only real time it becomes invalid is when you delete / free thread_data outside flashmq_plugin_allocate_thread_memory() and flashmq_plugin_deallocate_thread_memory(). Edit: and a good reason I should have used C++ style shared_ptr instead of C-style void. The only reason it's void, is for Mosquitto plugin v2 compatibility.