Q122848: PRB: #pragma code_seg() Affects Compiler-Generated Functions

Article: Q122848
Product(s): Microsoft C Compiler
Version(s): 1.0,2.0,2.1,4.0,5.0
Operating System(s): 
Keyword(s): kbcode kbCompiler kbCPPonly kbVC kbVC100 kbVC200 kbVC210 kbVC400 kbVC500
Last Modified: 15-FEB-2002

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The information in this article applies to:

- The C/C++ Compiler (CL.EXE), included with:
   - Microsoft Visual C++, 32-bit Editions, versions 1.0, 2.0, 2.1, 4.0 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 5.0 
   - Microsoft Visual C++, 32-bit Professional Edition, version 5.0 
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SYMPTOMS
========

When you use #pragma code_seg() in your C++ code, compiler-generated functions
are placed in the last code segment or section that is specified with #pragma
code_seg() instead of being placed in the default code segment or section.

RESOLUTION
==========

If you want compiler generated functions to be placed in the default code
segment, include an additional #pragma code_seg() that sets the code segment
back to the default:

     #pragma code_seg()

STATUS
======

This behavior is by design.

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

The following sample can be used to demonstrate this behavior. Compile the file
with /DMY_SECTION, and the compiler-generated code is placed in the MY_SECTION
section. To place the compiler-generated functions in the default code section,
compile without MY_SECTION defined.

You can determine into which section the code is placed by looking at the .COD
listing file, generated by using the /FAsc compiler option, or the linker
mapfile, generated by using the /MAP:filename link option.

Sample Code to Demonstrate Behavior
-----------------------------------

     /* Compile options needed: /Fc /DMY_SECTION
     */ 
     class base
     {
         int i;
     };

     class Simple: virtual base    // Classes with virtual base classes are
     {                             // non-trivial, and require constructors
     };

     #pragma code_seg("MY_SECTION")

     void main()
     {
         Simple Simple_Class;
     }

     #ifndef MY_SECTION           // Define MY_SECTION to cause compiler
     #pragma code_seg()           // generated code to be placed in the
     #endif                       // MY_SECTION section.

Additional query words: 8.00 9.00 pragma

======================================================================
Keywords          : kbcode kbCompiler kbCPPonly kbVC kbVC100 kbVC200 kbVC210 kbVC400 kbVC500 
Technology        : kbVCsearch kbAudDeveloper kbCVCComp
Version           : :1.0,2.0,2.1,4.0,5.0
Issue type        : kbprb

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