Q171438: PRB: Passing Arrays by Reference to OLE Objects Not Supported

Article: Q171438
Product(s): Microsoft FoxPro
Version(s): MACINTOSH:3.0b; WINDOWS:3.0,3.0b,5.0,5.0a
Operating System(s): 
Keyword(s): kbcode kbHWMAC kbvfp
Last Modified: 20-OCT-2000

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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 
- Microsoft Visual FoxPro for Macintosh, version 3.0b 
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SYMPTOMS
========

Microsoft Visual FoxPro does not support passing arrays by reference to OLE
objects.

STATUS
======

This behavior is by design.

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

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

1. Place the following code in a program file and add the program file to a
  project named OLETest. Compile the project into an OLE DLL or EXE named
  OLETest.

        DEFINE CLASS ARRAYTEST AS CUSTOM OLEPUBLIC
        NAME = "arraytest"

        PROCEDURE DOIT
           PARAMETER MYARRAY
           EXTERNAL ARRAY MYARRAY
           INSERT INTO foot (ONE,TWO,THREE,FOUR) VALUES ;
              (MYARRAY[1],MYARRAY[2],MYARRAY[3],MYARRAY[4])
           MYARRAY [1] = "100"
           MYARRAY [2] = "200"
           MYARRAY [3] = "300"
           MYARRAY [4] = "400"

           USE CURDIR() + "foot.dbf"
           INSERT INTO foot (ONE,TWO,THREE,FOUR) VALUES ;
              (MYARRAY[1],MYARRAY[2],MYARRAY[3],MYARRAY[4])
        ENDPROC

        PROCEDURE INIT
           SET UDFPARMS TO REFERENCE
           CREATE TABLE foot ;
              (ONE C(10),TWO C(10), THREE C(10), FOUR C(10))
        ENDPROC

        ENDDEFINE

2. After the OLE file is compiled, run the following code:

        CLEAR
        CLEAR ALL
        DIMENSION MYARRAY[4]
        MYARRAY(1) = "1"
        MYARRAY(2) = "2"
        MYARRAY(3) = "3"
        MYARRAY(4) = "4"
        OX = CREATEOBJECT("OLEtest.arraytest")
        OX.DOIT(@MYARRAY)
        ?OX.Name
        ?"MyArray from Calling Program"
        DISPLAY MEMORY LIKE MYARRAY
        RELEASE OX
        RELEASE MYARRAY
        USE foot
        BROWSE NOWAIT

3. Notice the first record of table "foot" contains the values placed in the
  array by the calling program. The second record contains the values PROCEDURE
  DOIT placed in the array. The DISPLAY MEMORY LIKE MYARRAY command, however,
  contains the original values of the array. Even though it appears that we are
  passing the array by reference to the OLE object, Microsoft Visual FoxPro is
  passing it by value.

Additional query words:

======================================================================
Keywords          : kbcode kbHWMAC kbvfp 
Technology        : kbHWMAC kbOSMAC kbVFPsearch kbAudDeveloper kbVFP300bMac kbVFP300 kbVFP300b kbVFP500 kbVFP500a
Version           : MACINTOSH:3.0b; WINDOWS:3.0,3.0b,5.0,5.0a
Issue type        : kbprb

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