Function sigwaitinfo 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn sigwaitinfo(
    set: *const sigset_t,
    sig: *mut siginfo_t,
) -> c_int

See https://pubs.opengroup.org/onlinepubs/9799919799/functions/sigwaitinfo.html.

Selects the pending signal from the set specified by set.

Upon success, returns the selected signal number. Upon failure, returns -1 and sets errno to indicate the error.