Function wcstoul 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn wcstoul(
    nptr: *const wchar_t,
    endptr: *mut *mut wchar_t,
    base: c_int,
) -> c_ulong

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

Converts the initial portion of the wide-character string pointed to by nptr to a type unsigned long.

Upon success, returns the converted value. If no conversion could be performed, returns 0.