Thread:1 Signal SIGAGBRT

Question

Why do I get a Thread:1 Signal SIGAGBRT within this code? I don't know what to change to fix the error. The application starts and as soon as I press the button the app cancels out and gives me an error.

import UIKit

class ViewController: UIViewController {

    @IBOutlet var textFieldInput: UITextField!
    @IBOutlet var laCelsius: UILabel!
    @IBOutlet var laFahrenheit: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


    @IBAction func btn(sender: UIButton) {

        var c_out = 0.0
        var f_out = 0.0
        var inputValue = 0.0

        let textInput = NSString(string: textFieldInput.text!)
        inputValue = textInput.doubleValue

        c_out = (inputValue-32)*5/9
        f_out = inputValue * 1.8 + 32

        self.laCelsius.text = NSString(format: "%3.2f" ,c_out) as String
        self.laFahrenheit.text = NSString(format: "%3.2f" ,f_out) as String

    }

}

this is the error code:

2016-09-22 14:15:51.669 DegreeCL[19045:1774964] -[DegreeCL.ViewController btnPressed:]: unrecognized selector sent to instance 0x7fa7bb643d40
2016-09-22 14:15:51.674 DegreeCL[19045:1774964] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[DegreeCL.ViewController btnPressed:]: unrecognized selector sent to instance 0x7fa7bb643d40'
*** First throw call stack:
(
    0   CoreFoundation                      0x000000010de1dd85 __exceptionPreprocess + 165
    1   libobjc.A.dylib                     0x000000010fbc1deb objc_exception_throw + 48
    2   CoreFoundation                      0x000000010de26d3d -[NSObject(NSObject) doesNotRecognizeSelector:] + 205
    3   CoreFoundation                      0x000000010dd6ccfa ___forwarding___ + 970
    4   CoreFoundation                      0x000000010dd6c8a8 _CF_forwarding_prep_0 + 120
    5   UIKit                               0x000000010e647a8d -[UIApplication sendAction:to:from:forEvent:] + 92
    6   UIKit                               0x000000010e7bae67 -[UIControl sendAction:to:forEvent:] + 67
    7   UIKit                               0x000000010e7bb143 -[UIControl _sendActionsForEvents:withEvent:] + 327
    8   UIKit                               0x000000010e7ba263 -[UIControl touchesEnded:withEvent:] + 601
    9   UIKit                               0x000000010e6ba99f -[UIWindow _sendTouchesForEvent:] + 835
    10  UIKit                               0x000000010e6bb6d4 -[UIWindow sendEvent:] + 865
    11  UIKit                               0x000000010e666dc6 -[UIApplication sendEvent:] + 263
    12  UIKit                               0x000000010e640553 _UIApplicationHandleEventQueue + 6660
    13  CoreFoundation                      0x000000010dd43301 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
    14  CoreFoundation                      0x000000010dd3922c __CFRunLoopDoSources0 + 556
    15  CoreFoundation                      0x000000010dd386e3 __CFRunLoopRun + 867
    16  CoreFoundation                      0x000000010dd380f8 CFRunLoopRunSpecific + 488
    17  GraphicsServices                    0x00000001124b3ad2 GSEventRunModal + 161
    18  UIKit                               0x000000010e645f09 UIApplicationMain + 171
    19  DegreeCL                            0x000000010dc38412 main + 114
    20  libdyld.dylib                       0x000000011068592d start + 1
    21  ???                                 0x0000000000000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb) 

Answer 1

The crucial information is

[DegreeCL.ViewController btnPressed:]: unrecognized selector sent to instance ...'

That means in Interface Builder there is somewhere a dead connection to an action btnPressed. Remove it.

You can search for btnPressed with ⇧⌘F.

Answer 2

SIGABRIT - signal is sent due to many reasons but in this case i think you have problem with Memory.

You should turn on All Exeptions with option of po $arg1 it will identify the error.

Answer 3

Select your button from interface builder, then select connection inspector from utilities and check that if you have extra connected action method should be there, remove it by clicking x and your issue will be solved!

It's should be btnPressed as per your crash log!