Function on_signing_stack 

pub fn on_signing_stack<F, T>(f: F) -> T
where
    F: FnOnce() -> T + Send,
    T: Send,

Run f on a dedicated worker thread with RECOMMENDED_SIGNING_STACK_BYTES of stack, returning its value.

This is the shared, audited guard for ML-DSA signing / keygen on small-stack native runtimes (notably the BEAM dirty-CPU scheduler). The calling thread blocks on the worker’s join, so this is synchronous from the caller’s point of view — it simply borrows a bigger stack for the duration of f.

The closure must return owned, Send values; keep any FFI term/handle construction on the caller so only plain data crosses the thread boundary. If f panics, the panic is propagated to the calling thread unchanged (via std::panic::resume_unwind), so catch_unwind and NIF panic handling behave exactly as if f had run inline.

Panics

Panics if the worker thread cannot be spawned (e.g. the OS refuses the stack reservation), or re-raises any panic that occurred inside f.

Examples

use metamorphic_crypto::on_signing_stack;

let sig = on_signing_stack(|| vec![0u8; 32]);
assert_eq!(sig.len(), 32);