示例

成功（实际大小与预期相符）

use pakr_assert_size::*;

#[repr(C, packed)]
#[assert_size(16)]
struct A {
    field1: u64,
    field2: u64,
}

#[assert_size(24)]
#[repr(C, packed)]
struct B {
    field1: u64,
    field2: u64,
    field3: u64,
}

失败（实际大小为 24 字节，预期为 32 字节）

use pakr_assert_size::*;

#[assert_size(32)]
#[repr(C, packed)]
struct C {
    field1: u64,
    field2: u64,
    field3: u64,
}

示例 assert_size_fits

成功（实际大小适合预期大小）

use pakr_assert_size::*;

// Exact match
#[repr(C, packed)]
#[assert_size_fits(16)]
struct A {
    field1: u64,
    field2: u64,
}

// Fits in match
#[assert_size_fits(32)]
#[repr(C, packed)]
struct B {
    field1: u64,
    field2: u64,
    field3: u64,
}

失败（实际大小为 24 字节，超过最大值 16 字节）

use pakr_assert_size::*;

#[assert_size_fits(16)]
#[repr(C, packed)]
struct C {
    field1: u64,
    field2: u64,
    field3: u64,
}