setControlCallback() - "Control Callback function must be an inline function" Error

[daniloprates]

setControlCallback() - "Control Callback function must be an inline function" Error

Problem

I'm developing a custom knob UI in HISE that draws a blob shape.
I want to click a button to regenerate the blob (change its randomness),
but I keep getting this error:

Control Callback function must be an inline function

I've tried:

• Making sure the function inside setControlCallback() is completely inline
• Avoiding external global variables inside setControlCallback()
• Using setAttribute() to store and retrieve blob data within the knob component
• Calling Content.repaint(); after updating values

None of these approaches work. The error persists.

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What I'm Trying to Achieve

1. I have a custom knob UI that draws a blob shape.
2. I want to click a button to regenerate the blob shape (change its randomness).
3. The knob should NOT update the blob shape—only the button should trigger the change.

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What’s Failing

Even when using a fully inline function like this:

btn.setControlCallback(function(component, value) {
    if (value) {
        Console.print("Blob Clicked! Generating new shape.");
        
        // Try storing data inside the knob to update later
        var knobComponent = Content.getComponent("knob1");
        knobComponent.setAttribute("blobData", generateBlob(9, 0.35, 0.1));

        Content.repaint(); // UI refresh
    }
});

I still get the error.

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Questions for the Community

1. What EXACTLY does HISE require to make an inline function "valid" inside setControlCallback()?
2. What is the best way to store dynamically changing data in a knob component?
3. Is there a different approach that avoids this error entirely?

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I’d appreciate any insights. Thanks!

[d.healey]

@daniloprates Was that post written by chat GPT?

An inline function is declared like this:

inline function myFunc(component, value)

I recommend you check out some of the example projects.

[daniloprates]

Yes, this was done by ChatGPT I tried to reply the post with this warning, but I didn't have the rights, as a new user.

Thanks David!

[Christoph Hart]

At some point we have to address that problem, I notice more and more posts just pasting the rubbish GPT output which dilutes the prestine information set available here in the forum.

Regarding the problem at hand, a single look at one of the many snippets / code examples from a good source should solve that problem, tuck inline before the function definition and pass it into the call.