KnowledgeBase Archive

An Archive of Early Microsoft KnowledgeBase Articles

View on GitHub

Q148202: BUG: Changes to Double-Precision Values in Debugger Fail

Article: Q148202
Product(s): Microsoft Fortran Compiler
Version(s): 4.0
Operating System(s): 
Keyword(s): kbFortranPS kbLangFortrankbbuglist
Last Modified: 03-NOV-1999

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

- Microsoft Fortran PowerStation for Windows 95 and Windows NT, version 4.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

When you change a single-precision number stored in a REAL*8 variable to a
double-precision number in one of the debugger's watch windows, you will not be
able to change the value again in the same debugging session. Furthermore, a
REAL*8 variable that is initialized with a double-precision number cannot have
its value changed in the debugger.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. We are researching this problem and will post new
information here in the Microsoft Knowledge Base as it becomes available.

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

Steps to Reproduce Problem
--------------------------

1. Build the following sample code in Developer Studio.

  C Compile options needed: /Zi

        real*8 DoubleVal1, DoubleVal2

        DoubleVal1 = 3.40E+38
        DoubleVal2 = 3.40D+40
        end

1. To invoke a debugging session in Developer Studio, click Debug on the Build
  menu, and then click Step Into.

2. In either the watch or quick watch window, type the variable names
  "DoubleVal1" (without the quotation marks) and "DoubleVal2" (without the
  quotation marks).

3. Change DoubleVal1 to a double-precision number by changing the exponent part
  to D+039 and pressing the ENTER key. Attempting to change the value of
  DoubleVal1 again in the current debugging session will not work. Attempting
  to change the value of DoubleVal2 after it has been initialized will fail.

Additional query words: 4.00

======================================================================
Keywords          : kbFortranPS kbLangFortran kbbuglist
Technology        : kbAudDeveloper kbPTProdChange kbFortranSearch kbFORTRANPower400NT
Version           : :4.0

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

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.