seize

Trait AsLink

Source 
pub unsafe trait AsLink { }
Expand description

A type that can be pointer-cast to and from a Link.

Most types can avoid this trait and work instead with the Linked wrapper type. However, if you want more control over the layout of your type (i.e. are working with a DST), you may need to implement this trait directly.

§Safety

Types implementing this trait must be marked #[repr(C)] and have a Link as their first field.

§Examples

use seize::{AsLink, Collector, Link};

#[repr(C)]
struct Bytes {
    // safety invariant: Link must be the first field
    link: Link,
    values: [*mut u8; 0],
}

// Safety: Bytes is repr(C) and has Link as it's first field
unsafe impl AsLink for Bytes {}

// Deallocate an `Bytes`.
unsafe fn dealloc(ptr: *mut Bytes, collector: &Collector) {
    collector.retire(ptr, |link| {
        // safety `ptr` is of type *mut Bytes
        let link: *mut Bytes = Link::cast(link);
        // ..
    });
}

Implementors§