Extra primitive types (u128, i128)

primitives, u128, i128



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Thanks to RFC 1504 “int128”, you can use i128 and u128 directly on nightly Rust starting from 1.16. Using the built-in types are preferred.

Extra primitive types for stable Rust. Currently includes:

  • u128 (unsigned 128-bit integers)
  • i128 (signed 128-bit integers)


You may also find other primitive types in other crates:


# Cargo.toml
extprim = "1"

If you want to use the u128!() and i128!() macros, please include the extprim_literals plugin.

# Cargo.toml
extprim = "1"
extprim_literals = "2"


extern crate extprim_literals;
extern crate extprim;

use std::str::FromStr;
use extprim::i128::i128;

fn main() {
    let a = i128::from_str("100000000000000000000000000000000000000").unwrap();
            // convert string to u128 or i128
    let b = i128::new(10).pow(38);
            // 64-bit integers can be directly new'ed
    assert_eq!(a, b);

    let c = i128::from_parts(5421010862427522170, 687399551400673280);
            // represent using the higher- and lower-64-bit parts
    let d = c - a;
            // standard operators like +, -, *, /, %, etc. work as expected.
    assert_eq!(d, i128::zero());

    const e: i128 = i128!(100000000000000000000000000000000000000);
            // use the literal macros
    assert_eq!(a, e);