DOCUMENT:Q172985 17-JUL-2001 [visualc] TITLE :FIX: Out of Order Definitions in idl May Cause Compiler Errors PRODUCT :Microsoft C Compiler PROD/VER:WINNT:5.0 OPER/SYS: KEYWORDS:kbCompiler kbCPPonly kbVC500bug kbVS97sp2fix ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - The C/C++ Compiler (CL.EXE), included with: - Microsoft Visual C++, 32-bit Enterprise Edition, version 5.0 - Microsoft Visual C++, 32-bit Professional Edition, version 5.0 ------------------------------------------------------------------------------- SYMPTOMS ======== When using the #import directive, errors may be generated due to the order in which definitions appear in the idl file used to generate the type library. The sample below causes error C2504, base class undefined, due to the interfaces being defined globally instead of in the library block. RESOLUTION ========== Move the interface definitions into the library block. - or - Create an extraneous reference to the class that the compiler is generating an error from within the library block. STATUS ====== Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This bug has been fixed in Visual Studio 97 Service Pack 3. For more information, please see the following article in the Microsoft Knowledge Base: Q170365 INFO: Visual Studio 97 Service Packs - What, Where, and Why MORE INFORMATION ================ Sample ------ // t.cpp // Compile options: /c #import "t.tlb" // t.idl // command line: midl t.idl // move the definitions of A and B into the // library block for one workaround [ uuid( 10000000-0000-0000-0000-000000000000 ) ] interface A : IUnknown { }; [ uuid( 20000000-0000-0000-0000-000000000000 ) ] interface B : A { }; [ uuid( 30000000-0000-0000-0000-000000000000 ) ] library Test { importlib("stdole2.tlb"); // uncomment this coclass for another workaround // [ hidden, uuid( 40000000-0000-0000-0000-000000000000 ) ] //coclass Dummy //{ // interface A; //} [ uuid( 50000000-0000-0000-0000-000000000000 ) ] coclass C { interface B; } } Additional query words: midl ====================================================================== Keywords : kbCompiler kbCPPonly kbVC500bug kbVS97sp2fix Technology : kbVCsearch kbAudDeveloper kbCVCComp Version : WINNT:5.0 Issue type : kbbug Solution Type : kbfix ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2001.