Sendable protocol for thread safety in Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a struct as conforming to the Sendable protocol.

Swift

struct DataModel: [1] {
    var value: Int
}

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AIdentifiable

BCodable

CSendable

DEquatable

Attempts:

3 left

💡 Hint

Common Mistakes

Using Codable instead of Sendable

Forgetting to conform to any protocol

To mark a struct as safe to use across threads, it must conform to the Sendable protocol.

2fill in blank

medium

Complete the code to mark a class as conforming to Sendable.

Swift

final class Counter: [1] {
    var count = 0
}

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AObservableObject

BSendable

CIdentifiable

DCodable

Attempts:

3 left

💡 Hint

Common Mistakes

Using ObservableObject instead of Sendable

Not marking the class as final when conforming to Sendable

Marking a class as Sendable indicates it is safe to use across threads.

3fill in blank

hard

Fix the error by completing the code to make the struct Sendable when it contains a non-Sendable property.

Swift

struct Wrapper: Sendable {
    var data: [1]
}

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AInt

BUnsafeMutablePointer<Int>

CString

DDispatchQueue

Attempts:

3 left

💡 Hint

Common Mistakes

Using pointer types which are not Sendable

Using DispatchQueue which is not Sendable

Only types that conform to Sendable can be used safely. Int is Sendable, but UnsafeMutablePointer and DispatchQueue are not.

4fill in blank

hard

Fill both blanks to create a Sendable struct with a computed property.

Swift

struct Point: [1] {
    var x: Int
    var y: Int
    var description: [2] {
        "(\(x), \(y))"
    }
}

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ASendable

BString

CInt

DCodable

Attempts:

3 left

💡 Hint

Common Mistakes

Using Codable instead of Sendable for the struct

Using Int instead of String for the description property

The struct conforms to Sendable and the computed property returns a String.

5fill in blank

hard

Fill all three blanks to create a Sendable struct with a closure property marked as @Sendable.

Swift

struct Task: [1] {
    var id: Int
    var action: [2] () -> Void
    init(id: Int, action: [3] () -> Void) {
        self.id = id
        self.action = action
    }
}

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ASendable

B@Sendable

C() -> Void

DCodable

Attempts:

3 left

💡 Hint

Common Mistakes

Not marking the closure as @Sendable

Using Codable instead of Sendable for the struct

The struct conforms to Sendable. The closure property and initializer parameter are marked @Sendable and have type () -> Void to ensure thread safety.