Suspend functions concept in Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a suspend function in Kotlin?

A suspend function is a special function that can pause its execution without blocking the thread, allowing other work to run. It can only be called from another suspend function or a coroutine.

beginner

How do you declare a suspend function in Kotlin?

You declare a suspend function by adding the suspend keyword before the fun keyword, like suspend fun fetchData().

intermediate

Why can't suspend functions be called directly from regular functions?

Suspend functions can pause execution, so they must be called from a coroutine or another suspend function that can handle this pausing. Regular functions don't support this behavior.

beginner

What happens when a suspend function calls delay()?

When a suspend function calls delay(), it pauses the function without blocking the thread, allowing other coroutines to run until the delay finishes.

beginner

Can suspend functions return values? How?

Yes, suspend functions can return values just like regular functions. You use the return keyword to return a value, and the caller receives it when the function resumes.

What keyword is used to declare a suspend function in Kotlin?

A suspend

B async

C await

D coroutine

The suspend keyword marks a function as suspendable.

Which of the following can call a suspend function directly?

A Regular function

B Java main method

C Coroutine or another suspend function

D Any function without restrictions

Suspend functions must be called from a coroutine or another suspend function.

What does a suspend function do when it calls delay()?

A Pauses without blocking the thread

B Runs in a new thread

C Throws an exception

D Blocks the thread

delay() pauses the suspend function without blocking the thread.

Can suspend functions return values?

A Only if they run on the main thread

B No, they cannot return values

C Only if they are marked with <code>async</code>

D Yes, just like regular functions

Suspend functions can return values normally using return.

Why are suspend functions useful?

A They make code run faster by using multiple threads

B They allow pausing without blocking threads, improving efficiency

C They replace all regular functions

D They automatically handle exceptions

Suspend functions let you pause work without blocking threads, so other tasks can run smoothly.

Explain what a suspend function is and why it is important in Kotlin coroutines.

Think about how suspend functions help manage waiting times without freezing the app.

Describe how you would call a suspend function from a regular Kotlin program.

Remember, you cannot call suspend functions directly from normal functions.