u32

u32 is a 32‑bit unsigned integer primitive type in Rust. It represents non-negative whole numbers and is one of several built-in integer types, alongside u8, u16, u64, u128, and usize.

The type stores values from 0 to 4294967295 inclusive and occupies four bytes of memory. In Rust, the associated constants are u32::MIN, which is 0, and u32::MAX, which is 4294967295.

Overflow behavior is defined by the language. In debug builds, arithmetic on integers that overflows will cause a panic, while in release builds the result wraps around. To manage arithmetic safely, Rust provides methods such as checked_add, overflowing_add, wrapping_add, and saturating_add, as well as analogous methods for subtraction, multiplication, and other operations.

Common uses for u32 include non-negative counters, indices in data structures where a fixed width is beneficial, bitfields, and identifiers in serialized data or network protocols. While indexing and lengths in Rust typically use usize, u32 is convenient for compact representations or when interfacing with formats that specify a 32‑bit unsigned field. Literals can be annotated with a suffix, such as 42u32, and the compiler can infer types from context. You can convert between integer types with as or TryFrom, though conversions may fail if values are out of range. For cross‑platform data exchange, endianness matters; u32 provides to_be and to_le methods to prepare values for big‑ or little‑endian representations, while the in‑memory representation follows the platform’s endianness.