rust/helpers/build_assert.c

Source file repositories/reference/linux-study-clean/rust/helpers/build_assert.c

File Facts

System
Linux kernel
Corpus path
rust/helpers/build_assert.c
Extension
.c
Size
1129 bytes
Lines
26
Domain
Rust Kernel Layer
Bucket
Rust API Membrane
Inferred role
Rust Kernel Layer: implementation source
Status
source implementation candidate

Why This File Exists

Rust-side wrappers and abstractions around kernel C APIs, ownership contracts, allocation, synchronization, and module integration.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0

#include <linux/build_bug.h>

/*
 * `bindgen` binds the C `size_t` type as the Rust `usize` type, so we can
 * use it in contexts where Rust expects a `usize` like slice (array) indices.
 * `usize` is defined to be the same as C's `uintptr_t` type (can hold any
 * pointer) but not necessarily the same as `size_t` (can hold the size of any
 * single object). Most modern platforms use the same concrete integer type for
 * both of them, but in case we find ourselves on a platform where
 * that's not true, fail early instead of risking ABI or
 * integer-overflow issues.
 *
 * If your platform fails this assertion, it means that you are in
 * danger of integer-overflow bugs (even if you attempt to add
 * `--no-size_t-is-usize`). It may be easiest to change the kernel ABI on
 * your platform such that `size_t` matches `uintptr_t` (i.e., to increase
 * `size_t`, because `uintptr_t` has to be at least as big as `size_t`).
 */
static_assert(
	sizeof(size_t) == sizeof(uintptr_t) &&
	__alignof__(size_t) == __alignof__(uintptr_t),
	"Rust code expects C `size_t` to match Rust `usize`"
);

Annotation

Implementation Notes