PRB: #pragma code_seg() Affects Compiler Generated Functions

• The Microsoft C/C++ Compiler (CL.EXE) included with: - Microsoft Visual C++, 32-bit Edition, versions 1.0, 2.0, 2.1, 4.0, 5.0

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 /Fc 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.