Function xcb::ffi::xproto::xcb_get_modifier_mapping_reply

pub unsafe extern fn xcb_get_modifier_mapping_reply(
    c: *mut xcb_connection_t, 
    cookie: xcb_get_modifier_mapping_cookie_t, 
    error: *mut *mut xcb_generic_error_t
) -> *mut xcb_get_modifier_mapping_reply_t

the returned value must be freed by the caller using libc::free().