Function bsd_auth_sys::auth_userchallenge

pub unsafe extern "C" fn auth_userchallenge(
    _name: *mut c_char, 
    _style: *mut c_char, 
    _type: *mut c_char, 
    _challengep: *mut *mut c_char
) -> *mut auth_session_t

Create a BSD Authentication session, and get a challenge for a challenge-response authentication flow

From authenticate(3):

Takes the same `name`, `style`, and `type` argments as does `auth_userokay()`. However,
rather than authenticating the user, it returns a possible challenge in the pointer pointed
to by `challengep`. The return value of the function is a pointer to a newly created BSD
Authentication session. This challenge, if not NULL, should be displayed to the user.