PRB: Causes and Resolutions for Error RW4005

ID: Q123989

1.00 1.50 | 7.00 

WINDOWS   | MS-DOS
kbtool kberrmsg kbprb

The information in this article applies to: 

   The Resource Compiler (RC.EXE) included with:
    - Microsoft C/C++ for MS-DOS, version 7.0
    - Microsoft Visual C++ for Windows, versions 1.0 and 1.5

SYMPTOMS

The following error is generated by the resource compiler (RC): 

   warning RW4005: Segment XX (offset XXXX) contains a
      relocation record pointing to the automatic data segment.
      This will cause the program to crash if the instruction being
      fixed up is executed in a multi-instance application. If this
      fixup is necessary, the program should be restricted to run
      only a single instance.

CAUSE

This error results when a fix-up record attempts to fix DGROUP, the data segment created by the C run-time, in the code segment of an application that might have multiple instances. Because Windows version 3.1 cannot fix locations that are different from instance to instance in shared code segments, this error is generated.

RESOLUTION

Here are five possible causes and solutions:

1. Your program is not suitable for running multiple instances. The 

   program has a fix-up record that references the data segment or DGROUP.
   In a multiple instance application, this causes problems because every
   instance of the application references that same data segment.
   Typically, there are no fix-ups from the data segment because DS will
   contain the data segment value.

   Remember that there is no guarantee that you will be able to create
   multiple instance large model applications by using the /Gx compiler
   switch, especially if you have global C++ class objects. See the
   documentation for this compiler switch for more information.
2. This warning has been reported to be caused by a reference to '__fac' 
   made by the C/C++ version 7.0 compiler. The code does not make a
   reference to DS to access static data but to a constant value that is
   fixed-up when the code is loaded. No such reports have connected the
   same problem with Visual C++.

   If DS can be loaded with a different value when a second instance
   of an application is run, the code can be reused without crashing.
   In the version of the code which uses the constant value for
   referencing data, the second instance of an application might
   write over the first instance's data.

   The reported solution to this problem is to turn off the fast compile
   option. (Use the /f- switch to specify the full optimizing compiler
   instead.) This should stop the compiler from referencing the
   constant.
3. The /GD compile switch optimizes prolog and epilog code for functions in 
   DLL files and is inappropriate for use when compiling modules for
   applications (EXE files). Removing the /GD compiler switch should
   correct the problem.
4. This warning can be reproduced by creating a function that uses the 
   __loadds keyword or some inline assembly code that loads the segment of
   DGROUP into a register.
5. If you have a DATA MULTIPLE statement in your .DEF file, change it to 
   DATA SINGLE. This will allow only one copy of the data segment to
   exist. NOTE: Putting the code into a DLL would have the same effect.
Additional reference words: 1.00 1.50 3.10 7.00 errmsg err msg KBCategory: kbtool kbprb kberrmsg KBSubcategory: TlsMisc Keywords : kb16bitonly

Last Reviewed: July 23, 1997