Function dwg_dynapi_entity_value 

pub unsafe extern "C" fn dwg_dynapi_entity_value(
    entity: *mut c_void,
    dxfname: *const c_char,
    fieldname: *const c_char,
    out: *mut c_void,
    fp: *mut Dwg_DYNAPI_field,
) -> bool

Returns the ENTITY|OBJECT.fieldname value in out. entity is the Dwg_Entity_ENTITY or Dwg_Object_OBJECT struct with the specific fields. The optional Dwg_DYNAPI_field *fp is filled with the field types from dynapi.c.