pub type OptionReplaceWithFn = unsafe fn(option: PtrMut, value: Option<PtrConst>);Expand description
Replace an existing option with a new value
§Safety
The option parameter must point to aligned, initialized memory of the correct type.
The old value will be dropped.
If replacing with Some, value is moved out of (with core::ptr::read) —
it should be deallocated afterwards but NOT dropped.