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Q121289: PRB: Unreferenced Symbols Don’t Appear in .BSC File

Article: Q121289
Product(s): Microsoft C Compiler
Version(s): 1.0,1.5,1.51
Operating System(s): 
Keyword(s): kbprb
Last Modified: 25-JUL-2001

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The information in this article applies to:

- Microsoft Visual C++, versions 1.0, 1.5, 1.51 
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SYMPTOMS
========

Unless a symbol is referenced in a program, it will not appear in the browser
database.

CAUSE
=====

This problem is due to the default behaviors of the Compiler (CL.EXE) and how it
handles browser files (.SBR files), as well as the Browser Database Maintenance
Utility (BSCMAKE.EXE) and how it handles browser databases (.BSC files).

NOTE: This article does not apply to Microsoft Visual C++, 32-bit Edition,
version 2.0 and above. In these versions, when the compiler option "Don't Pack
Info" is selected, the option /Zn is added to the CL compile line. Subsequently,
the option /Iu is automatically added to BSCMAKE.EXE.

RESOLUTION
==========

By understanding the default behaviors, you can discover where unreferenced
symbols are defined. The default behavior of the Compiler when using the /FR or
/Fr switches is to pack browser files, removing information about where
unreferenced symbols are defined. To prevent the Compiler from doing this
packing, use the /Zn switch from the command line, or check the "Don't Pack
Information" checkbox under:

  Options...|Project...|Compiler...|Listing Files

Similarly, the default behavior of BSCMAKE is to not record information about
unreferenced symbols when building the browser database for an application. To
turn off this behavior, use the /Iu switch from the command line.

NOTE: There is no way to control BSCMAKE's behavior when using a Visual
Workbench-generated makefile. The hard-coded default BSCMAKE command line used
by the Visual Workbench doesn't include the /Iu option. In the case of a Visual
Workbench-generated makefile, find the inference rule within the makefile
generated by the Visual Workbench that causes the BSCMAKE utility to be
executed. There, change the command line that is passed to the BSCMAKE utility.
To do this, open the makefile as a text file and find the $(PROJ).BSC: inference
rule. You should see the BSCMAKE command on the next line or two. Just add the
/Iu option as shown in this example:

  $(PROJ).BSC: $(SBRS)
      bscmake@<<
  /Iu /o$@ $(SBRS)
  <<

NOTE: There is an important caveat here. When you use the internal build engine
of the Visual Workbench, the inference rule portion of the makefile is not used.
Instead, the Visual Workbench uses the inference rules only when the file is
opened as an external makefile. For this solution to work, the makefile must be
opened as an external makefile in the Visual Workbench or the project must be
built with NMAKE from the command line.

NOTE: The Compiler and BSCMAKE work independently. BSCMAKE builds the browser
database from browser (.SBR) files generated at compile time. Unreferenced
symbols will not appear in the browser database if:

- CL.EXE is executed with /Fr or /FR, and without the /Zn option, regardless of
  whether BSCMAKE is executed with the /Iu option. Omitting the /Zn option
  causes browser file packing to discard information about unreferenced
  symbols.

- CL.EXE is executed with /Fr or /FR, and /Zn, and BSCMAKE is executed without
  the /Iu option. Omitting the /Iu option causes BSCMAKE to ignore information
  about unreferenced symbols.

In order for the solutions presented here to work, both of these must be true:

- The Compiler must be executed with /Fr or /FR, and /Zn.

- BSCMAKE must be executed with the /Iu option in the same build.

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

An unreferenced symbol is a symbol that has been defined, but never appears in
the body of code apart from its definition. Common examples of defined but
unreferenced symbols are instances of CWinApp-derived classes in MFC
applications and variables of any type that are not used in an application.

Additional query words: 1.00 1.50 1.51

======================================================================
Keywords          : kbprb 
Technology        : kbVCsearch kbAudDeveloper kbvc150 kbvc100 kbVC151
Version           : :1.0,1.5,1.51
Issue type        : kbprb

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

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