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•Created by RedTShirtGaming on 7/4/2024 in #help

async functions always finish on a background thread

Hello! I'm experienced with C#, but I'm just starting to learn about async functions and multithreading. I'm having an issue where a function that contains 'await Task.Run(...)' always finishes running on a background thread and not the main thread that it was called from. Here is my code

internal static async Task GenerateChunkAsync(Dictionary<Vector3Int, Chunk> chunks)
{
    // Any main-thread setup here

    var chunkData = await Task.Run(() =>
    {
        // Execute code on a background thread
        var data = SomeFunc(5);
        return data;
    });

    // Finish running on the main thread (important for opengl)
    // For some reason, this always runs on the background thread that the Task.Run code was running on
    Console.WriteLine($"Finished function in {chunkData}ms. Is main thread: {Engine.IsMainThread}");
}

private static long SomeFunc(int sleepTime)
{
    var timer = new System.Diagnostics.Stopwatch();
    timer.Start();
    
    // Simulate some background work
    Thread.Sleep(sleepTime * 1000);
    
    timer.Stop();
    return timer.ElapsedMilliseconds;
}

internal static async Task GenerateChunkAsync(Dictionary<Vector3Int, Chunk> chunks)
{
    // Any main-thread setup here

    var chunkData = await Task.Run(() =>
    {
        // Execute code on a background thread
        var data = SomeFunc(5);
        return data;
    });

    // Finish running on the main thread (important for opengl)
    // For some reason, this always runs on the background thread that the Task.Run code was running on
    Console.WriteLine($"Finished function in {chunkData}ms. Is main thread: {Engine.IsMainThread}");
}

private static long SomeFunc(int sleepTime)
{
    var timer = new System.Diagnostics.Stopwatch();
    timer.Start();
    
    // Simulate some background work
    Thread.Sleep(sleepTime * 1000);
    
    timer.Stop();
    return timer.ElapsedMilliseconds;
}

Is there a way of ensuring that the function that was called from the main thread always finishes running on the main thread? Thanks :D

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