IDL's input is an xxx.idl and (optionally) an xxx.acf file. Its default output is a header (xxx.h) file, that contains definitions and declarations derived from the input for general use in the development source code, and two stub files, one for the client and one for the server, which contain runtime code for marshalling and unmarshalling, message handling, and all the other details of managing network communications. The stub files are output as object code (xxx_cstub.o and xxx_sstub.o) suitable for linking with the developer's compiled code. The IDL compiler generates C source code as an intermediate step in the compilation process, and the output of this step can also be saved in a pair of files (xxx_cstub.c and xxx_sstub.c).
In order for a pair of client and server stubs to interoperate, they should be generated from the same interface definition (.idl) file, but they do not have to be generated with the same attribute configuration file (.acf). The compatibility rules for interface version numbers also apply (see the OSF DCE Application Development Guide - Core Components ).
For further information on the IDL compiler, see the idl(1rpc)reference page in the OSF DCE Command Reference.