Function guile_sys::scm_make_port_type

pub unsafe extern "C" fn scm_make_port_type(
    name: *mut c_char, 
    fill_input: Option<extern "C" fn(_: SCM) -> c_int>, 
    write: Option<unsafe extern "C" fn(_: SCM, _: *const c_void, _: size_t)>
) -> scm_t_bits