macro_rules! offset_of { ($parent:path, $field:tt) => { ... }; }
Expand description
Calculates the offset of the specified field from the start of the named struct.
§Examples
use memoffset::offset_of;
#[repr(C, packed)]
struct Foo {
a: u32,
b: u64,
c: [u8; 5]
}
fn main() {
assert_eq!(offset_of!(Foo, a), 0);
assert_eq!(offset_of!(Foo, b), 4);
}
§Notes
Rust’s ABI is unstable, and type layout can be changed with each compilation.
Using offset_of!
with a repr(Rust)
struct will return the correct offset of the
specified field
for a particular compilation, but the exact value may change
based on the compiler version, concrete struct type, time of day, or rustc’s mood.
As a result, the value should not be retained and used between different compilations.