Function std::ptr::replace 1.0.0 (const: unstable)[−][src]
pub unsafe fn replace<T>(dst: *mut T, src: T) -> TExpand description
Moves src into the pointed dst, returning the previous dst value.
Neither value is dropped.
This function is semantically equivalent to mem::replace except that it
operates on raw pointers instead of references. When references are
available, mem::replace should be preferred.
Safety
Behavior is undefined if any of the following conditions are violated:
-
dstmust be valid for both reads and writes. -
dstmust be properly aligned. -
dstmust point to a properly initialized value of typeT.
Note that even if T has size 0, the pointer must be non-null and properly aligned.
Examples
use std::ptr;
let mut rust = vec!['b', 'u', 's', 't'];
// `mem::replace` would have the same effect without requiring the unsafe
// block.
let b = unsafe {
ptr::replace(&mut rust[0], 'r')
};
assert_eq!(b, 'b');
assert_eq!(rust, &['r', 'u', 's', 't']);Run