Function core::slice::from_ptr_range

const: unstable · source · []
pub unsafe fn from_ptr_range<'a, T>(range: Range<*const T>) -> &'a [T]
🔬 This is a nightly-only experimental API. (slice_from_ptr_range #89792)
Expand description

Forms a slice from a pointer range.

This function is useful for interacting with foreign interfaces which use two pointers to refer to a range of elements in memory, as is common in C++.


Behavior is undefined if any of the following conditions are violated:

  • The start pointer of the range must be a valid and properly aligned pointer to the first element of a slice.

  • The end pointer must be a valid and properly aligned pointer to one past the last element, such that the offset from the end to the start pointer is the length of the slice.

  • The range must contain N consecutive properly initialized values of type T:

    • The entire memory range of this slice must be contained within a single allocated object! Slices can never span across multiple allocated objects.
  • The memory referenced by the returned slice must not be mutated for the duration of lifetime 'a, except inside an UnsafeCell.

  • The total length of the range must be no larger than isize::MAX. See the safety documentation of pointer::offset.

Note that a range created from slice::as_ptr_range fulfills these requirements.


The lifetime for the returned slice is inferred from its usage. To prevent accidental misuse, it’s suggested to tie the lifetime to whichever source lifetime is safe in the context, such as by providing a helper function taking the lifetime of a host value for the slice, or by explicit annotation.



use core::slice;

let x = [1, 2, 3];
let range = x.as_ptr_range();

unsafe {
    assert_eq!(slice::from_ptr_range(range), &x);