CODEWITHSUNDEEP
swiftfunctionswift3
KasaiJo
KasaiJo

Reputation: 128

Error call function (instance member cannot be used)

It's not a duplicate cause with lazy i have an issu too : "A C function pointer cannot be formed from a closure that captures context"

In my main class I have "detectChangeMidi" but in this code, when I try to call a function I don't understand why I can't. (i can't use var too, anything of my class)

I'm not expert in swift, then try to explain to me what's going one. I use the CoreMidi librarie.

UPDATE :

I replace the code by minimaliste code for better entendement.

import Foundation
import CoreMIDI

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        gestionMidi()
        //...
    }

    func gestionMidi() {
        //...
        let midiNotif:MIDINotifyProc = detectChangeMidi
        MIDIClientCreate("Swift3 Test Client" as CFString, midiNotif, nil, &midiClient)
        //...
    }

    func plop(){
        print("bla bla bla")
    }

    let detectChangeMidi: @convention(c) (UnsafePointer<MIDINotification>, UnsafeMutableRawPointer?) -> Swift.Void =
    { midiNotification,unkown   in
        var notification = midiNotification.pointee

        self.plop()     //problem here
        //...
    }
}

Upvotes: 0

Views: 416

Answers (2)

matt
matt

Reputation: 536009

Your entire agenda here is misguided; it is not at all obvious what you can be trying to do. You cannot declare a property or function as being convention(c) and also refer to self. But you don't need to! If your goal is to pass a function as a parameter where a C pointer-to-function is expected, just pass the function. Anyway you'll have a much easier time in Swift if you call MIDIClientCreateWithBlock(_:_:_:) instead.

Upvotes: 1

inokey
inokey

Reputation: 6190

The problem is with the scope as I can judge from the error message.

Also the thing to get attention to is that you're executing plop() in closure, and that requires self.plop().

also midiNotification,unkown in - unkown seems to be a typo.

Check where you declare the function itself. From this snippet it's hard to understand what's your declaration scope.

Upvotes: 0

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