rustix/
bitcast.rs

1//! The `bitcast` and `bitflags_bits` macros.
2
3#![allow(unused_macros)]
4
5// Ensure that the source and destination types are both primitive integer
6// types and the same size, and then bitcast.
7macro_rules! bitcast {
8    ($x:expr) => {{
9        if false {
10            // Ensure the source and destinations are primitive integer types.
11            let _ = !$x;
12            let _ = $x as u8;
13            0
14        } else if false {
15            // Ensure that the source and destinations are the same size.
16            // SAFETY: This code is under an `if false`.
17            #[allow(
18                unsafe_code,
19                unused_unsafe,
20                clippy::useless_transmute,
21                clippy::missing_transmute_annotations
22            )]
23            unsafe {
24                ::core::mem::transmute($x)
25            }
26        } else {
27            // Do the conversion.
28            $x as _
29        }
30    }};
31}
32
33/// Return a [`bitcast`] of the value of `$x.bits()`, where `$x` is a
34/// `bitflags` type.
35macro_rules! bitflags_bits {
36    ($x:expr) => {{
37        bitcast!($x.bits())
38    }};
39}
rustix/bitcast.rs

rustix/
bitcast.rs
