# Function std::mem::size_of_val

1.0.0 (const: unstable) · source ·

    pub fn size_of_val<T>(val: &T) -> usizewhere
        T: ?Sized,

Expand description

Returns the size of the pointed-to value in bytes.

This is usually the same as `size_of::<T>()`. However, when `T` has no statically-known size, e.g., a slice `[T]` or a trait object, then `size_of_val` can be used to get the dynamically-known size.

## Examples

    use std::mem;

    assert_eq!(4, mem::size_of_val(&5i32));

    let x: [u8; 13] = [0; 13];
    let y: &[u8] = &x;
    assert_eq!(13, mem::size_of_val(y));

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