Attribute Macro global_heap_allocator

#[global_heap_allocator]

A macro attribute to register the global heap allocator.

The attributed static variable will be used to provide heap allocation for the kernel.

This attribute is not to be confused with Rust’s built-in [global_allocator] attribute, which applies to a static variable implementing the unsafe GlobalAlloc trait. In contrast, the global_heap_allocator attribute does not require the heap allocator to implement an unsafe trait. global_heap_allocator eventually relies on [global_allocator] to customize Rust’s heap allocator.

Example

use core::alloc::{AllocError, Layout};
use ostd::{mm::heap::{GlobalHeapAllocator, HeapSlot}, global_heap_allocator};

// Of course it won't work and all allocations will fail.
// It's just an example.
#[global_heap_allocator]
static ALLOCATOR: MyHeapAllocator = MyHeapAllocator;

struct MyHeapAllocator;

impl GlobalHeapAllocator for MyHeapAllocator {
    fn alloc(&self, _layout: Layout) -> Result<HeapSlot, AllocError> { None }
    fn dealloc(&self, _slot: HeapSlot) -> Result<(), AllocError> {}
}