#[derive(Pod)]
{
// Attributes available to this derive:
#[bytemuck]
}
Expand description
Derive the Pod
trait for a struct
The macro ensures that the struct follows all the the safety requirements
for the Pod
trait.
The following constraints need to be satisfied for the macro to succeed
- All fields in the struct must implement
Pod
- The struct must be
#[repr(C)]
or#[repr(transparent)]
- The struct must not contain any padding bytes
- The struct contains no generic parameters, if it is not
#[repr(transparent)]
§Examples
#[derive(Copy, Clone, Pod, Zeroable)]
#[repr(C)]
struct Test {
a: u16,
b: u16,
}
#[derive(Copy, Clone, Pod, Zeroable)]
#[repr(transparent)]
struct Generic<A, B> {
a: A,
b: PhantomData<B>,
}
If the struct is generic, it must be #[repr(transparent)]
also.
ⓘ
#[derive(Copy, Clone, Pod, Zeroable)]
#[repr(C)] // must be `#[repr(transparent)]`
struct Generic<A> {
a: A,
}
If the struct is generic and #[repr(transparent)]
, then it is only Pod
when all of its generics are Pod
, not just its fields.
#[derive(Copy, Clone, Pod, Zeroable)]
#[repr(transparent)]
struct Generic<A, B> {
a: A,
b: PhantomData<B>,
}
let _: u32 = bytemuck::cast(Generic { a: 4u32, b: PhantomData::<u32> });
ⓘ
struct NotPod;
let _: u32 = bytemuck::cast(Generic { a: 4u32, b: PhantomData::<NotPod> });