Rust: What is the difference between as_ptr and as_mut_ptr?

as_ptr — immutable pointer. as_mut_ptr — mutable pointer.

as_ptr:

• Returns *const T.
• Immutable.
• For FFI.

as_mut_ptr:

• Returns *mut T.
• Mutable.
• For FFI.

1let v = vec![1, 2, 3];
2let ptr = v.as_ptr();
3unsafe { println!("{}", *ptr); }
4
5let mut v = vec![1, 2, 3];
6let ptr = v.as_mut_ptr();
7unsafe { *ptr = 10; }

Key: as_ptr for reading, as_mut_ptr for writing.