## Release MFC Libraries for MS-DOS Limited to 286 and Up

Q118614

    7.00   | 1.00 1.50
    MS-DOS | WINDOWS
    kbprg

    ----------------------------------------------------------------------
    The information in this article applies to:

     - The Microsoft Foundation Classes (MFC) included with:

        - Microsoft C/C++ version 7.0
        - Microsoft Visual C++ for Windows, versions 1.0 and 1.5
    ----------------------------------------------------------------------

    SUMMARY
    =======

    The release version of the MFC libraries for MS-DOS are built with the /O1
    option, which also implies the /G2 option. Because the /G2 option places
    80286-processor-specific code in the library that is being built, programs
    built with this library are incompatible with 8086(8088) and 80186(80188)
    processors. One symptom of this incompatibility is that the MS-DOS program
    may crash when run on either an 8086(8088) or an 80186(80188) machine.

    The debug version of the MFC libraries for MS-DOS are built using the /Od
    option, so 80286-specific code is not generated for the debug libraries.

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

    To change this behavior, edit the makefile that is provided in the
    \MSVC\MFC\SRC directory and rebuild the library. Use the steps below to
    edit the makefile so that the /O1 option is not used for release builds of
    the MFC libraries for MS-DOS:

    1. Go to the NON-DEBUG OPTIONS section of the makefile.

    2. Find the DEBOPTS= line.

    3. Change "/O1" to "/f- /Oe /Os /Ob1 /OV4 /Gs /Gf /Gy" (without the
       quotes).

    4. Save the file.

    To rebuild the library, follow the instructions in the README.TXT file,
    which is located in the \MSVC\MFC\SRC directory.

    Additional reference words: kbinf 7.00 1.00 1.50 2.00 2.50
    KBCategory: kbprg
    KBSubcategory: MfcMisc

Keywords : kb16bitonly
Issue type :
Technology : kbAudDeveloper kbMFC

Last Reviewed: May 5, 2001 © 2001 Microsoft Corporation. All rights reserved. Terms of Use.