Function presser::get_maybe_uninit_at_offset_mut

pub fn get_maybe_uninit_at_offset_mut<'a, T, S: Slab + ?Sized>(
    slab: &'a mut S,
    offset: usize
) -> Result<&'a mut MaybeUninit<T>, Error>

Gets a mutable reference to a MaybeUninit<T> within slab at offset.

• offset is the offset, in bytes, after the start of slab at which a T may be placed.

The function will return an error if:

• offset within slab is not properly aligned for T
• offset is out of bounds of the slab
• offset + size_of::<T> is out of bounds of the slab

Safety

This function is safe since in order to read any data you need to call the unsafe MaybeUninit::assume_init on the returned value. However, you should know that if you do that, you must have ensured that there is indeed a valid* T in its place.

Note that if you write through the returned reference, any padding bytes within the layout of T (which for a repr(Rust) type is arbitrary and unknown) must thereafter be considered uninitialized until you explicitly initialize them again. This means that if you write a T which contains padding into slab, you must not, for example, try to read those bytes as &[u8] afterwards (or as some other type which expects those bytes to be initialized), as you would then be reading uninitialized memory, which is undefined behavior.

* Validity is a complex topic not to be taken lightly. See this rust reference page for more details.