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mutable reference

A reference that lets you change the value it points to.

A mutable reference &mut T allows changing the referent; only one may exist at a time.

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Examples

  • fn add_point(score: &mut u32) { *score += 1; } called as add_point(&mut score) changes main's own variable.

  • Two &mut x borrows in use at the same time are rejected with E0499.

See also

reference borrow checker data race
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