Q191327: FIX: Double Value Returned from DLL Gets Decimal Portion of 0

Article: Q191327
Product(s): Microsoft FoxPro
Version(s): WINDOWS:3.0,3.0b,5.0,5.0a
Operating System(s): 
Keyword(s): 
Last Modified: 11-DEC-1999

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b, 5.0, 5.0a 
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SYMPTOMS
========

If you create a .dll file that contains an exported function, which returns a
value of type Double, when you declare and call this function from Visual
FoxPro, any decimal portion of the return value is set to 0.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. This bug has been corrected in Visual FoxPro 6.0.

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

Steps to Reproduce Behavior
---------------------------

1. In Microsoft Visual C++, create test2.cpp which will contain the following
  code:

        //test2.cpp
        #include <windows.h>

        BOOL APIENTRY DllMain(HANDLE hInst, DWORD ul_reason_to_call, LPVOID
     lpReserved)
        {
            return TRUE;
                UNREFERENCED_PARAMETER(hInst);
                UNREFERENCED_PARAMETER(ul_reason_to_call);
                UNREFERENCED_PARAMETER(lpReserved);
        };

        double APIENTRY test(double p1, double p2)
        {
         return p1 * p2;
        };

2. Create a file called Test2.DEF with the following contents:

        ; test2.def : Declares the module parameters for the DLL.

        LIBRARY      "Test2"
        DESCRIPTION  'Test2 Dynamic Link Library'

        EXPORTS
           test @4

3. Build Test2.dll as a Multithreaded .dll file.

4. In Visual FoxPro, set the directory containing the .dll built in Step 4 as
  the default directory.

5. Run the following from the Command window:

        DECLARE DOUBLE test IN test2.dll DOUBLE, DOUBLE
        ? test(1.5, 1.5)
        ? test(2.5, 2.5)

  You will get return values of:

  2.00
  6.00

Any decimal portion of the double value returned from the .dll function will be
0.

REFERENCES
==========

(c) Microsoft Corporation 1998, All Rights Reserved.
Contributions by Jim Saunders, Microsoft Corporation


Additional query words: kbVFp500abug kbVFp300bbug kbVFp600fix kbInterOp kbfvp600fix

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Keywords          :  
Technology        : kbVFPsearch kbAudDeveloper kbVFP300 kbVFP300b kbVFP500 kbVFP500a
Version           : WINDOWS:3.0,3.0b,5.0,5.0a
Issue type        : kbbug
Solution Type     : kbfix

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