Function nf_enter 

#[unsafe(no_mangle)]
pub(crate) unsafe extern "C" fn nf_enter(
    context: *const Context,
    function: u32,
    span: u32,
) -> bool

Counts a call into function function from the call at span, failing when calls are too deep. Each successful call is matched by nf_leave.

Safety

See the module’s contract.