Concurrency safety guarantees in Rust - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the Send trait guarantee in Rust?

The Send trait guarantees that ownership of a type can be safely transferred to another thread.

beginner

What is the purpose of the Sync trait in Rust?

The Sync trait means a type can be safely referenced from multiple threads at the same time.

intermediate

Why does Rust prevent data races at compile time?

Rust uses ownership, borrowing rules, and traits like Send and Sync to ensure no two threads can simultaneously access mutable data without synchronization, preventing data races.

intermediate

How does Rust's type system help with concurrency safety?

Rust's type system enforces rules that prevent unsafe sharing of data across threads by requiring types to implement Send and Sync traits for thread transfer and shared access.

beginner

What happens if a type does not implement Send or Sync?

If a type does not implement Send or Sync, Rust will not allow it to be transferred or shared across threads, preventing unsafe concurrent access.

Which Rust trait allows a type to be safely transferred between threads?

A Clone

B Send

C Copy

D Sync

The Send trait marks types that can be safely moved to another thread.

What does the Sync trait ensure?

A A type can be referenced from multiple threads safely

B A type can be copied

C A type can be cloned

D A type can be sent to another process

Sync means it is safe for multiple threads to have references to the same data.

Why does Rust prevent data races at compile time?

A Because Rust uses garbage collection

B Because Rust uses runtime checks

C Because Rust disables multithreading

D Because Rust enforces ownership and borrowing rules

Rust's ownership and borrowing rules prevent unsafe concurrent mutable access.

If a type is not Send, what does Rust do?

A Prevents it from being transferred between threads

B Allows it to be sent between threads anyway

C Automatically implements <code>Send</code> for it

D Ignores thread safety

Rust will not allow types that are not Send to be moved across threads.

Which of these is NOT a concurrency safety guarantee in Rust?

A No data races

B Safe transfer of ownership between threads

C Automatic locking of all variables

D Safe shared references across threads

Rust does not automatically lock variables; it enforces safety through types and traits.

Explain how Rust uses the Send and Sync traits to guarantee concurrency safety.

Think about what each trait allows in terms of thread interaction.

Describe why Rust's compile-time checks prevent data races in concurrent programs.

Focus on how Rust controls access to data across threads.