Sendable protocol for thread safety in Swift - Mini Project: Build & Apply

Using the Sendable Protocol for Thread Safety in Swift

📖 Scenario: You are building a simple Swift program that shares data safely between threads. Swift's Sendable protocol helps ensure data can be passed between threads without causing problems.

🎯 Goal: Learn how to mark a custom struct as Sendable and use it safely across threads.

📋 What You'll Learn

Create a struct called Message with a text property of type String

Make Message conform to the Sendable protocol

Create a constant message of type Message with the text "Hello from thread!"

Use DispatchQueue.global().async to print the message.text safely from a background thread

💡 Why This Matters

🌍 Real World

In real apps, data often moves between threads. Marking data as Sendable helps prevent bugs and crashes when sharing data safely.

💼 Career

Understanding Sendable is important for Swift developers working on apps that use concurrency, such as iOS apps with background tasks.

1

Create the Message struct

Create a struct called Message with a single property text of type String.

Swift

# Define the Message struct with a text property
# Your code here

Need a hint?

Use struct Message { let text: String } to create the struct.

2

Make Message conform to Sendable

Make the Message struct conform to the Sendable protocol by adding : Sendable after the struct name.

Swift

struct Message: Sendable {
    let text: String
}
# Your code here

Need a hint?

Add : Sendable right after Message in the struct declaration.

3

Create a Message instance

Create a constant called message of type Message with the text exactly set to "Hello from thread!".

Swift

struct Message: Sendable {
    let text: String
}

# Create the message constant here
# Your code here

Need a hint?

Use let message = Message(text: "Hello from thread!") to create the instance.

4

Print message.text safely from a background thread

Use DispatchQueue.global().async to print message.text from a background thread.

Swift

struct Message: Sendable {
    let text: String
}

let message = Message(text: "Hello from thread!")

# Print message.text on a background thread
# Your code here

Need a hint?

Use DispatchQueue.global().async { print(message.text) } to print safely on a background thread.