CODEWITHSUNDEEP
c++multithreadingwinapiprogress-bar
Ben
Ben

Reputation: 57227

Best way to update progress bar from thread

I've got a long-running task that is executed in a thread.

The code for this all takes place in a separate class than the WinMain() entry point, say WorkerClass.

I'd like to update a progress bar every so often with the progress of the task.

After several hours of research, trial, and error, I've come across several methods:

A) Custom PostMessage to main window proc from inside the thread (problem: frowned upon by several sources: thread should not touch main UI)

B) Custom PostMessage to main window proc from some WorkerClass function (problem: running into scope issues between free vs class functions, since thread function has to be free of class)

C) Worker thread updates int pointer, then a UI-thread timer updates UI periodically (problem: worth spending time on, or is this "doing it wrong")

A lot of the discussion dives into MFC or C# which I'm not interested in.

I'm to the point where I've run into roadblocks with all three methods. It will be several hours to do a good job on figuring one out - I don't want to put in effort learning it wrong.

Which one should I pursue?

Upvotes: 2

Views: 4190

Answers (1)

Ryan Guthrie
Ryan Guthrie

Reputation: 688

FWIW: The code base I currently work on posts a message to the main thread.

Another method, and the one I prefer, is the Observer Pattern. The main thread would "subscribe" to the worker and whenever the worker updates itself, it notifies its observers (any object that subscribed to it). http://en.wikipedia.org/wiki/Observer_pattern

Upvotes: 2

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