[−][src]Trait typelayout::FromZeros

pub unsafe trait FromZeros {
    fn zeroed() -> Self
    where
        Self: Sized,
    { ... }
}

Working Example

This marker trait is implemented for structs iff it is ReprC, has no padding bytes, and all fields are also FromZeros:

use typelayout::{ReprC, Generic, Layout, FromZeros};

#[derive(Generic, Default, Debug, PartialEq)]
#[repr(C)]
pub struct Struct {
  first: u8,
  second: u8,
}

unsafe impl ReprC for Struct {}

assert_eq!(<Struct as Default>::default(), <Struct as FromZeros>::zeroed());

Failing Example

This marker trait is not implemented if a type has padding:

use typelayout::{ReprC, Generic, Layout, FromZeros};

#[derive(Generic, Default, Debug, PartialEq)]
#[repr(C)]
pub struct Struct {
  first: u8,
  second: u16, // padding will be inserted between `first` and `second`
}

unsafe impl ReprC for Struct {}

// `Struct` does not implement `FromZeros`, because it has a padding byte!
assert_eq!(<Struct as Default>::default(), <Struct as FromZeros>::zeroed());