Function std::alloc::set_alloc_error_hook
source · pub fn set_alloc_error_hook(hook: fn(_: Layout))
alloc_error_hook
#51245)Expand description
Registers a custom allocation error hook, replacing any that was previously registered.
The allocation error hook is invoked when an infallible memory allocation fails — that is,
as a consequence of calling handle_alloc_error
— before the runtime aborts.
The allocation error hook is a global resource. take_alloc_error_hook
may be used to
retrieve a previously registered hook and wrap or discard it.
§What the provided hook
function should expect
The hook function is provided with a Layout
struct which contains information
about the allocation that failed.
The hook function may choose to panic or abort; in the event that it returns normally, this will cause an immediate abort.
Since take_alloc_error_hook
is a safe function that allows retrieving the hook, the hook
function must be sound to call even if no memory allocations were attempted.
§The default hook
The default hook, used if set_alloc_error_hook
is never called, prints a message to
standard error (and then returns, causing the runtime to abort the process).
Compiler options may cause it to panic instead, and the default behavior may be changed
to panicking in future versions of Rust.
§Examples
#![feature(alloc_error_hook)]
use std::alloc::{Layout, set_alloc_error_hook};
fn custom_alloc_error_hook(layout: Layout) {
panic!("memory allocation of {} bytes failed", layout.size());
}
set_alloc_error_hook(custom_alloc_error_hook);
Run