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#![feature(allocator_api, slice_ptr_get)]
use std::alloc::{Allocator as _, Global, GlobalAlloc, Layout, System};
#[global_allocator]
static ALLOCATOR: Allocator = Allocator;
struct Allocator;
unsafe impl GlobalAlloc for Allocator {
unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
// use specific size to avoid getting triggered by rt
if layout.size() == 123 {
println!("Allocated!")
}
System.alloc(layout)
}
unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
if layout.size() == 123 {
println!("Dellocated!")
}
System.dealloc(ptr, layout)
}
}
fn main() {
// Only okay because we explicitly set a global allocator that uses the system allocator!
let l = Layout::from_size_align(123, 1).unwrap();
let ptr = Global.allocate(l).unwrap().as_non_null_ptr(); // allocating with Global...
unsafe {
System.deallocate(ptr, l);
} // ... and deallocating with System.
let ptr = System.allocate(l).unwrap().as_non_null_ptr(); // allocating with System...
unsafe {
Global.deallocate(ptr, l);
} // ... and deallocating with Global.
}
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