Files parsed by MkTypLib are .odl files. Files parsed by MIDL are referred to as .idl files, although they can contain the same syntax elements as .odl files. The MIDL compiler and the MkTypLib utility both compile scripts written in ODL. However, MkTypLib is obsolete and you should use the MIDL compiler instead. The following sections describe the differences and special considerations for using MkTypLib and MIDL to create type libraries.