Function std::ptr::slice_from_raw_parts

pub const fn slice_from_raw_parts<T>(data: *const T, len: usize) -> *const [T]

Forms a raw slice from a pointer and a length.

The len argument is the number of elements, not the number of bytes.

This function is safe, but actually using the return value is unsafe. See the documentation of slice::from_raw_parts for slice safety requirements.

Examples

use std::ptr;

// create a slice pointer when starting out with a pointer to the first element
let x = [5, 6, 7];
let raw_pointer = x.as_ptr();
let slice = ptr::slice_from_raw_parts(raw_pointer, 3);
assert_eq!(unsafe { &*slice }[2], 7);

You must ensure that the pointer is valid and not null before dereferencing the raw slice. A slice reference must never have a null pointer, even if it’s empty.

use std::ptr;
let danger: *const [u8] = ptr::slice_from_raw_parts(ptr::null(), 0);
unsafe {
    danger.as_ref().expect("references must not be null");
}