1.0.0[−][src]Function alloc::slice::from_raw_parts
pub unsafe fn from_raw_parts<'a, T>(data: *const T, len: usize) -> &'a [T]
Forms a slice from a pointer and a length.
The len
argument is the number of elements, not the number of bytes.
Safety
This function is unsafe as there is no guarantee that the given pointer is
valid for len
elements, nor whether the lifetime inferred is a suitable
lifetime for the returned slice.
data
must be non-null and aligned, even for zero-length slices. One
reason for this is that enum layout optimizations may rely on references
(including slices of any length) being aligned and non-null to distinguish
them from other data. You can obtain a pointer that is usable as data
for zero-length slices using NonNull::dangling()
.
The total size of the slice must be no larger than isize::MAX
bytes
in memory. See the safety documentation of pointer::offset
.
Caveat
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.
Examples
use std::slice; // manifest a slice for a single element let x = 42; let ptr = &x as *const _; let slice = unsafe { slice::from_raw_parts(ptr, 1) }; assert_eq!(slice[0], 42);