projects/linux·blob master · refs

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1// SPDX-License-Identifier: GPL-2.0
2
3//! Foreign function interface (FFI) types.
4//!
5//! This crate provides mapping from C primitive types to Rust ones.
6//!
7//! The Rust [`core`] crate provides [`core::ffi`], which maps integer types to the platform default
8//! C ABI. The kernel does not use [`core::ffi`], so it can customise the mapping that deviates from
9//! the platform default.
10
11#![no_std]
12
13macro_rules! alias {
14 ($($name:ident = $ty:ty;)*) => {$(
15 #[allow(non_camel_case_types, missing_docs)]
16 pub type $name = $ty;
17
18 // Check size compatibility with `core`.
19 const _: () = assert!(
20 ::core::mem::size_of::<$name>() == ::core::mem::size_of::<::core::ffi::$name>()
21 );
22 )*}
23}
24
25alias! {
26 // `core::ffi::c_char` is either `i8` or `u8` depending on architecture. In the kernel, we use
27 // `-funsigned-char` so it's always mapped to `u8`.
28 c_char = u8;
29
30 c_schar = i8;
31 c_uchar = u8;
32
33 c_short = i16;
34 c_ushort = u16;
35
36 c_int = i32;
37 c_uint = u32;
38
39 // In the kernel, `intptr_t` is defined to be `long` in all platforms, so we can map the type to
40 // `isize`.
41 c_long = isize;
42 c_ulong = usize;
43
44 c_longlong = i64;
45 c_ulonglong = u64;
46}
47
48pub use core::ffi::c_void;
49
50pub use core::ffi::CStr;