1.0.0[−][src]Function std::ptr::swap
pub unsafe fn swap<T>(x: *mut T, y: *mut T)
Swaps the values at two mutable locations of the same type, without deinitializing either.
But for the following two exceptions, this function is semantically
equivalent to mem::swap
:

It operates on raw pointers instead of references. When references are available,
mem::swap
should be preferred. 
The two pointedto values may overlap. If the values do overlap, then the overlapping region of memory from
x
will be used. This is demonstrated in the second example below.
Safety
Behavior is undefined if any of the following conditions are violated:

Both
x
andy
must be valid for both reads and writes. 
Both
x
andy
must be properly aligned.
Note that even if T
has size 0
, the pointers must be nonNULL and properly aligned.
Examples
Swapping two nonoverlapping regions:
use std::ptr; let mut array = [0, 1, 2, 3]; let x = array[0..].as_mut_ptr() as *mut [u32; 2]; // this is `array[0..2]` let y = array[2..].as_mut_ptr() as *mut [u32; 2]; // this is `array[2..4]` unsafe { ptr::swap(x, y); assert_eq!([2, 3, 0, 1], array); }Run
Swapping two overlapping regions:
use std::ptr; let mut array = [0, 1, 2, 3]; let x = array[0..].as_mut_ptr() as *mut [u32; 3]; // this is `array[0..3]` let y = array[1..].as_mut_ptr() as *mut [u32; 3]; // this is `array[1..4]` unsafe { ptr::swap(x, y); // The indices `1..3` of the slice overlap between `x` and `y`. // Reasonable results would be for to them be `[2, 3]`, so that indices `0..3` are // `[1, 2, 3]` (matching `y` before the `swap`); or for them to be `[0, 1]` // so that indices `1..4` are `[0, 1, 2]` (matching `x` before the `swap`). // This implementation is defined to make the latter choice. assert_eq!([1, 0, 1, 2], array); }Run