Loading...

How to get rid of 'Result of call to function is unused' warning in Swift/Xcode?

question swift xcode
Ram Patra Published on October 8, 2023
Swift 5.0+

In Swift, if you encounter a “Result of call to ‘function’ is unused” warning, it means that you’re calling a function that returns a value (typically a result type, such as Result or any other type), but you’re not doing anything with the result. To get rid of this warning, you have a few options depending on the specific situation:

  1. Use the Result Value: If the function returns a result, it’s usually important to handle the result appropriately. You should evaluate the result and take action based on whether it’s a success or a failure. You can use a switch statement or if conditions to handle the result:

    let result = someFunctionThatReturnsAResult()
    
    switch result {
    case .success(let value):
        // Handle the success case
        print("Success: \(value)")
    case .failure(let error):
        // Handle the failure case
        print("Error: \(error)")
    }
    
  2. Discard the Result: If you’re intentionally ignoring the result (for example, if you’re calling a function solely for its side effects and don’t care about the result), you can use an underscore (_) to explicitly indicate that you’re intentionally discarding the result:

    _ = someFunctionThatReturnsAResult()
    

    Using _ tells the Swift compiler that you’re aware of the result but don’t need to use it.

  3. Suppress the Warning: If you have a specific reason to suppress the warning for a particular line of code (though this is generally not recommended), you can use the @discardableResult attribute:

    @discardableResult
    func someFunctionThatReturnsAResult() -> ResultType {
        // Function implementation
    }
    

    Adding @discardableResult indicates that callers are allowed to discard the result without triggering a warning.

It’s important to choose the option that best aligns with the intended behavior of your code. In most cases, you should handle the result or at least acknowledge that you’re intentionally discarding it to make your code more readable and maintainable.

Presentify

Take your presentation to the next level.

FaceScreen

Put your face and name on your screen.

ToDoBar

Your to-dos on your menu bar.

Ram Patra Published on October 8, 2023
Image placeholder

Keep reading

If this article was helpful, others might be too

question swiftui macos September 3, 2024 Two ways to open a window programmatically in SwiftUI

SwiftUI provides an openWindow environment variable on macOS that allows you to open windows programmatically. Here’s how you can use it to open a new window when a button is clicked:

question swiftui swift September 2, 2024 Combine in SwiftUI and how you can rewrite the same code using async await

Combine is Apple’s declarative framework for handling asynchronous events and data streams in Swift. Introduced in SwiftUI and iOS 13, Combine leverages reactive programming principles, allowing developers to process values over time and manage complex asynchronous workflows with clarity and efficiency.

question swiftui swift September 30, 2023 How to open the Settings view in a SwiftUI app on macOS 14.0 (Sonoma)?

In macOS 14.0 (Sonoma), Apple removed support for NSApp.sendAction to open the Settings view in your SwiftUI app. You now have to use SettingsLink like below: