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https://github.com/openharmony/third_party_rust_memoffset.git
synced 2026-07-18 12:25:36 -04:00
Josh Stone
a5cc37c558
The compiler now raises a deny-by-default `const_err` lint on this test, which doesn't let it get to the expected `#[should_panic]`. We can allow that lint in order to let the test hit the error it wants.
memoffset
C-Like offset_of functionality for Rust structs.
Introduces the following macros:
offset_of!for obtaining the offset of a member of a struct.span_of!for obtaining the range that a field, or fields, span.
memoffset works under no_std environments.
Usage
Add the following dependency to your Cargo.toml:
[dependencies]
memoffset = "0.2"
Add the following lines at the top of your main.rs or lib.rs files.
#[macro_use]
extern crate memoffset;
Examples
#[repr(C, packed)]
struct Foo {
a: u32,
b: u32,
c: [u8; 5],
d: u32,
}
assert_eq!(offset_of!(Foo, b), 4);
assert_eq!(offset_of!(Foo, c[3]), 11);
assert_eq!(span_of!(Foo, a), 0..4);
assert_eq!(span_of!(Foo, a .. c), 0..8);
assert_eq!(span_of!(Foo, a .. c[1]), 0..9);
assert_eq!(span_of!(Foo, a ..= c[1]), 0..10);
assert_eq!(span_of!(Foo, ..= d), 0..14);
assert_eq!(span_of!(Foo, b ..), 4..17);