Re: IDL help, argh argh argh

From:

"Alexander Nickolov" <agnickolov@mvps.org>

Newsgroups:

microsoft.public.vc.atl

Date:

Mon, 22 Jan 2007 10:14:32 -0800

Message-ID:

<eSbLrElPHHA.320@TK2MSFTNGP06.phx.gbl>

Don't use explicit paths. Use additional include directories
in your project settings under the C/C++ - General tab.

Defining your structs etc in the base IDL should suffice.
They should be visible in your C++ source file provided
you include the header file generated from the dependent
IDL. That one has a #include for the header generated
from the base IDL.

--
=====================================
Alexander Nickolov
Microsoft MVP [VC], MCSD
email: agnickolov@mvps.org
MVP VC FAQ: http://vcfaq.mvps.org
=====================================

"Jason S" <jmsachs@gmail.com> wrote in message
news:1169487032.052368.244820@a75g2000cwd.googlegroups.com...

Is there a guide to Good IDL Practices for Dummies?

I am having the toughest time w/ IDL files if I try to split them up
between build trees when there are shared definitions for
structs/enums/interfaces/typedefs that need to be defined in one place
so I can share them between projects. Very painful.

Here's what I know so far, can anyone answer my questions below?
What should be in an IDL file:
Part 1: internal stuff
import "oaidl.idl";
import "ocidl.idl";
import "IDLBASE.IDL"; // if your IDL refers to another of your IDL
files, include it here
/* your interfaces, structs, enum, typedef, etc. */

Part 2: library declaration to create a .tlb file
library XLib
{
// declare any of the interfaces, structs, etc. above that you want to
have show up in the type library
// define coclasses here

importlib("stdole32.tlb");
importlib("stdole2.tlb");
importlib("IDLBASE.TLB"); // if your IDL refers to another IDL file
with a type library, include it here
}

Questions:
(1) build tree hell
Suppose I have two directories {root}/IDL1 and {root}/IDLBASE. There
are files {root}/IDLBASE/IDLBASE.idl and {root}/IDL1/IDL1/idl. IDL1.idl
includes/imports IDLBASE. How do I deal with the file path mess in the
IDL file? Do I leave out explicit paths completely and use MIDL's /I
switch?

The problem I seem to be running into is that if my IDL1 file includes
"#import "../IDLBASE/IDLBASE.idl", then MIDL seems to produce some
files (the _p.c file at least) with corresponding #include statemenst
that ignore my explicit paths that I've given in the IDL file.

(2) Let's say I want IDLBASE to contain a struct or enum or typedef,
and I have a project PRJ1 with IDL file PRJ1.IDL. I want to use the
struct/enum/typedef both in PRJ1.IDL and in my C++ files in PRJ1. Where
do I put the struct / enum / typedef so that it shows up properly in my
C++ project?

build dependency looks something like this (where X -> Y means Y
depends on X)
IDLBASE.idl -> PRJ1.idl -> PRJ1.h (autogenerated from MIDL) ->
my_class.cpp (#includes PRJ1.h)