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Q194299: PRB: RC2151 When Using MFC as a Static Link Library

Article: Q194299
Product(s): Microsoft C Compiler
Version(s): winnt:4.0,4.1,4.2,4.2b,5.0,6.0
Operating System(s): 
Keyword(s): kbMFC kbResource kbResourceEd kbString kbVC400 kbVC500 kbVC600 kbGrpDSMFCATL
Last Modified: 17-JUL-2001

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The information in this article applies to:

- The Microsoft Foundation Classes (MFC), used with:
   - Microsoft Visual C++, 32-bit Editions, versions 4.0, 4.1, 4.2b 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 4.2 
   - Microsoft Visual C++, 32-bit Professional Edition, version 4.2 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 5.0 
   - Microsoft Visual C++, 32-bit Professional Edition, version 5.0 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 6.0 
   - Microsoft Visual C++, 32-bit Professional Edition, version 6.0 
   - Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
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SYMPTOMS
========

Adding a string resource to an application that uses MFC as a static link
library may result in the use of the same ID value twice in a STRINGTABLE
statement. The Resource Compiler generates the following error:

  RC2151 Cannot re-use string constants

This problem is likely to happen when using the resource editor to add the
string.

CAUSE
=====

When using MFC as a static library in an application, MFC's resources are
compiled into the .exe.

The statement on line 26 of Afxres.rc

  #ifndef _AFXDLL

causes string resources defined in Afxres.h to be used in the application when
building Afxres.rc. If an ID value of another string resource matches any of the
ID values used in Afxres.rc, the same ID value is used twice in a STRINGTABLE
statement.

NOTE: The problem is not multiple definitions of the ID symbol, but rather, the
use of the definition multiple times in a string table.

RESOLUTION
==========

Consult both Technical Note 20 "ID Naming and Numbering Conventions" and the
file Afxres.h to help locate ID values used by Windows or MFC. Then remove any
entries in the string table that use ID values more than once (for example, an
entry in the application's string table that has a ID value matching an ID value
in Afxres.h).

STATUS
======

This behavior is by design.

MORE INFORMATION
================

Technical Note 20 "ID Naming and Numbering Conventions" lists many of the ID
ranges used for specific purposes. However, this article does not mention the
possible conflict with the IDs defined in Afxres.h.

Steps to Reproduce Behavior
---------------------------

1. Create a new SDI or MDI application using AppWizard that use MFC as a static
  library.

2. Add a String resource using the Resource Editor; it will have the ID
  IDS_STRING61446, which has the value 61446 (0xF006).

3. Build the application.

When building the application, the following error message is generated:

  error RC2151 : cannot reuse string constants, 61446(0xF006)

This error is generated because AFX_IDS_UNNAMED_FILE is defined with the value of
0xF006 in Afxres.h and is used in both the Afxres.rc file and the application's
.rc file.

REFERENCES
==========

For additional information, please see the following article(s) in the Microsoft
Knowledge Base:

  Q21569 RW2002 Error "Cannot Reuse String Constants" in RC.EXE

(c) Microsoft Corporation 1998, All Rights Reserved. Contributions by Isaac
Varon, Microsoft Corporation


Additional query words:

======================================================================
Keywords          : kbMFC kbResource kbResourceEd kbString kbVC400 kbVC500 kbVC600 kbGrpDSMFCATL 
Technology        : kbAudDeveloper kbMFC
Version           : winnt:4.0,4.1,4.2,4.2b,5.0,6.0
Issue type        : kbprb

=============================================================================

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