Borrowing
Borrowing is Rust’s mechanism for accessing a value through a reference without transferring ownership, subject to rules governing reference validity and aliasing.
Refactoring to Rust
Rust's borrowing rules constrain the number, mutability, and validity of references to a value.
- How it is used
- Lets functions use a value repeatedly without taking ownership, including when reading an NGINX request through a reference.
- How deep it goes
- Defines reference-count, mutability, and validity rules, then applies them to a moved-value error and an unsafe pointer conversion.
- Examples
- Uses repeated artwork viewing and an NGINX request-body handler to show ordinary borrowing and checked pointer conversion.
- What you can do after
- Practice/perform it by passing artwork by reference and checking pointer validity before borrowing an NGINX request.
Rust Servers, Services, and Apps
Borrowing is Rust's mechanism for granting temporary access to a value without transferring its ownership.
- How it is used
- Uses borrowing to provide temporary value access while preserving Rust’s explicit ownership model.
- How deep it goes
- Defines immutable and mutable references and compiler rules, but does not develop implementation examples or lifetime syntax.
- Examples
- Uses `&T` for shared access and `&mut T` for exclusive mutation.
- What you can do after
- Evaluate/understand how Rust permits temporary access without ownership transfer or invalid memory access.
Read how Rust Servers, Services, and Apps explains borrowing →
Rust in Action: Systems programming concepts and techniques
Borrowing is Rust's mechanism for temporarily accessing a value through a reference without taking ownership of it.
- How it is used
- Uses references to give functions access to values without moving ownership, avoiding moved-value errors in a satellite messaging program.
- How deep it goes
- Explains read-only and mutable reference syntax through a worked mailbox program and states the one-read-write-borrow limit.
- Examples
- Contrasts a repeated satellite status call that fails after a move with a mailbox that uses &mut CubeSat to send messages.
- What you can do after
- Diagnose/debug moved-value errors and use read-only or mutable references when a function needs access rather than ownership.
Read how Rust in Action: Systems programming concepts and techniques explains borrowing →
Related concepts
- referenceproduces · A reference is an indirect value or relationship that identifies or provides access to another value, object, resource, or source.
- borrow checkerused by · A borrow checker is a compile-time mechanism that verifies ownership, borrowing, and reference rules to prevent invalid memory access.
- ownershipalternative to · Ownership is a programming-language model that assigns responsibility for controlling a value or resource, including its lifetime and eventual cleanup.
- Rustpart of · Rust is a statically typed systems programming language designed for performance, concurrency, and memory safety without requiring garbage collection.
- mutable referenceimplemented by · A mutable reference is a reference or handle through which the referenced value or storage location may be modified, subject to language-specific access rules.
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