Q121457: Using Microsoft FORTRAN 5.1 with Visual Basic

Article: Q121457
Product(s): Microsoft Fortran Compiler
Version(s): 3.0,5.1
Operating System(s): 
Keyword(s): kbfile
Last Modified: 06-FEB-2002

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The information in this article applies to:

- Microsoft FORTRAN Compiler for MS-DOS, version 5.1 
- Microsoft Visual Basic Standard Edition for Windows, version 3.0 
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SUMMARY
=======

This article contains the complete text of Application Note number HF1047. The
title of this Application Note is "HF1047: Using FORTRAN 5.1 with Visual
Basic."

HF1047 describes how to call FORTRAN routines in a .dll from a Visual Basic for
Windows-based application, and how to create the .dll file from FORTRAN code.

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

The following file is available for download from the Microsoft Download
Center:

  hf1047.exe
  (http://download.microsoft.com/download/fortranps10bnt/doc1/1/W9XNT4/EN-US/hf1047.exe)

For additional information about how to download Microsoft Support files, click
the article number below to view the article in the Microsoft Knowledge Base:

  Q119591 How to Obtain Microsoft Support Files from Online Services

Microsoft used the most current virus detection software available on the date of
posting to scan this file for viruses. Once posted, the file is housed on secure
servers that prevent any unauthorized changes to the file.

Or you can have this Application Note faxed or mailed to you by calling Microsoft
Product Support Services Monday through Friday, 6:00 A.M. to 6:00 P.M. Pacific
time. If you are outside the United States, contact the Microsoft subsidiary for
your area. To locate your subsidiary, go to the Microsoft Web site

  http://www.microsoft.com/worldwide/default.htm

THE TEXT OF HF1047
------------------

======================================================================
 Microsoft(R) Product Support Services Application Note (Text File)
           HF1047: USING FORTRAN 5.1 WITH VISUAL BASIC(R)
======================================================================
                                                  Revision Date: 9/94
                                                     No Disk Included

-----------------------------------------------------------------------
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| the use of this Application Note. This Application Note may be      |
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| must be copied without modification (the MS-DOS(R)  utility         |
| diskcopy is appropriate for this purpose);  3) All components of    |
| this Application Note must be distributed together;  and  4) This   |
| Application Note may not be distributed for profit.                 |
|                                                                     |
| Copyright (C) 1994 Microsoft Corporation.  All Rights Reserved.     |
| Visual Basic, Microsoft, and MS-DOS are registered trademarks and   |
| Windows is a trademark of Microsoft Corporation.                    |
|---------------------------------------------------------------------|

FORTRAN AND VISUAL BASIC FOR WINDOWS(TM)
========================================

There are several points to consider when using FORTRAN from Visual
Basic:

- Calling FORTRAN routines from Visual Basic for Windows requires
  that the FORTRAN routines be made into a DLL.

- When passing data:

   - Both FORTRAN and Visual Basic pass data by reference.
   - Visual Basic strings are different from FORTRAN strings. They
     include a string structure, and require a special declaration
     ("ByVal") to force Visual Basic to pass the string pointer.
   - In Visual Basic, array indices start at 0. In FORTRAN, they
     start at 1.

- There must be a declaration statement in Visual Basic for each
  FORTRAN routine that will be called.

- FORTRAN DLLs have two significant problems in file I/O:

   - Unformatted or Binary files can't be accessed with FORTRAN
     commands.
   - ASCII files that are opened in FORTRAN will not be readable
     until you exit from Visual Basic.

  The solution to both problems is to use Windows API calls to do
  file I/O.

  NOTE: For additional information on file I/O, please see the
  following article in the Microsoft Knowledge Base:

  ARTICLE-ID: Q102698
       TITLE: Performing File I/O from a FORTRAN Dynamic-Link Library

CREATING A FORTRAN DLL CALLED FROM A VISUAL BASIC PROGRAM
=========================================================

This lab presents the steps required to build a FORTRAN DLL and shows how
to create a Visual Basic application that uses this DLL. This lab also
shows the syntax required to pass various types of data between FORTRAN and
Visual Basic.

Preparation
-----------

1. Install FORTRAN version 5.1 to target 'MS-DOS and Windows' and
  include the Windows DLL library. When this is completed
  successfully, the files \FORTRAN\BINB\FL.DEF and
  \FORTRAN\LIB\LDLLFEW.LIB will be on your computer

  NOTE: If there are problems with any of this, please use the
  additional information provided in the following article in the
  Microsoft Knowledge Base:

  ARTICLE-ID: Q112006
       TITLE: FORTRAN 5.1 Setup Procedure for Typical Installations

2. Install Visual Basic version 3.0.

3. Read chapters 1 and 2 of the "Visual Basic Programmers Guide," and do
  the "Hello World" example.

Procedure
---------

1. Start Visual Basic, and begin a new project.

2. Add the following items to the Form by dragging them from the Tool
  Box to the Form:

   - Four command buttons
   - One text box

3. In the Properties Window, modify the properties of the following items:

  Object               Properties      Setting
  ----------------------------------------------------
  Form                 Caption         VB/Fortran Lab
  Text Box             Text            empty
                       Multi Line      True
                       Scroll Bars     3 Both
  Command Button 1     Caption         Test Array
  Command Button 2     Caption         Test String
  Command Button 3     Caption         Test String Array
  Command Button 4     Caption         Test Square

  At this point, the Form should look something like this:

-------------------------------------------------------------------
|                          VB/Fortran Lab                         |
-------------------------------------------------------------------
|                                                                 |
|                               -------------------------------   |
|  -------------------------    |                           | |   |
|  |      Test Array       |    |                           | |   |
|  -------------------------    |                           | |   |
|  -------------------------    |                           | |   |
|  |      Test String      |    |                           | |   |
|  -------------------------    |                           | |   |
|  -------------------------    |                           | |   |
|  |   Test String Array   |    |                           | |   |
|  -------------------------    |                           | |   |
|  -------------------------    |                           | |   |
|  |      Test Square      |    |                           | |   |
|  -------------------------    |                           | |   |
|                               |                           | |   |
|                               |---------------------------| |   |
|                               -------------------------------   |
-------------------------------------------------------------------

4. From the Project Window, select View Code for the Form.

5. Add the Visual Basic code as follows:

  Add the following code to the Command1 Click event:

     Sub Command1_Click ()
        Static arr(1 To 3, 1 To 7) As Single
        Call ARRAYTEST(arr(1, 1))
        For i% = 1 To 3
           For j% = 1 To 7
              ' Enter the following two lines as one, single line of code:
              text1.Text = Str$(arr(i%, j%)) + Chr$(13) + Chr$(10)
                 + text1.Text
           Next j%
        Next i%
     End Sub

  Add the following code to the Command2 Click event:

     Sub Command2_Click ()
        Dim temp As String * 40
        Call STRINGER(temp)
        text1.Text = temp + Chr$(13) + Chr$(10) + text1.Text
     End Sub

  Add the following code to the Command3 Click event:

     Sub Command3_Click ()
        Static testarray(1 To 5) As StringArray
        Call ARRAYSTRING(testarray(1))
        For i% = 1 To 5
           ' Enter the following two lines as one, single line of code:
           text1.Text = testarray(i%).strings + Chr$(13) +
              Chr$(10) + text1.Text
        Next i%
     End Sub

  Add the following code to the Command4 Click event:

     Sub Command4_Click ()
        Dim a As Single
        a = 4.2
        Call Square(a)
        text1.Text = Str$(a) + Chr$(13) + Chr$(10) + text1.Text
     End Sub

6. Create the files for the form by choosing Save Project As from
  the file menu. In a directory of your choice, save the form as
  VB-FORT.FRM, and save the project as VB-FORT.MAK. Create a new module,
  and save it as GLOBAL.BAS.

7. From the Project Window, select View Code for GLOBAL.BAS. Add all of
  the following code to general declarations section in GLOBAL.BAS:

     Type StringArray
        strings As String * 24
     End Type

     Declare Sub ARRAYTEST Lib "fortvb.dll" (Myarray As Single)
     Declare Sub STRINGER Lib "fortvb.dll" (ByVal mystring As String)
     Declare Sub ARRAYSTRING Lib "fortvb.dll" (Myarray As StringArray)
     Declare Sub Square Lib "fortvb.dll" (a As Single)

  NOTE: The DLL name in these declarations could include full path to
  the FORTRAN DLL (For example, "C:\VB\TEXT\FORTVB.DLL"). Then Visual
  Basic won't have to search for it.

8. Create the FORTRAN file to be made into a DLL as follows:

  Create a file (FORTVB.FOR) with the following contents, and place it
  in the same directory where the Form and other Visual Basic files
  are located:

     C  Code for the FORTRAN DLL 'FORTVB.DLL'
           subroutine arraystring(arr)
           character*24 arr(5)
           arr = 'This is a string also'
           end

           subroutine arraytest(arr)
           real*4 arr(3,7)
           integer i,j
           do i=1,3
             do j=1,7
               arr(i,j) = 11*i+j-1*i
             end do
           end do
           end

           subroutine square(a)
           real*4 a
           a = a*a
           end

           subroutine stringer(s)
           character*40 s
           s = 'This is from fortran'
           end

9. Create the Definitions file as follows:

  Create the file FORTVB.DEF with the following contents:

     LIBRARY        FORTVB
     EXETYPE        WINDOWS
     PROTMODE
     CODE           PRELOAD MOVEABLE DISCARDABLE
     DATA           PRELOAD MOVEABLE SINGLE
     HEAPSIZE       1024

     EXPORTS        WEP
                    ARRAYTEST
                    ARRAYSTRING
                    SQUARE
                    STRINGER

10. Build the DLL by typing the following commands at the MS-DOS prompt
   in the directory where the Form and other Visual Basic files
   are located:

      FL /c /Gw /Aw /G2 FORTVB.FOR
      LINK FORTVB,FORTVB.DLL,NUL,/NOD LDLLFEW,FORTVB.DEF

11. Copy the DLL to a directory where Visual Basic can find it if the
   declarations did not include the full path to the DLL. This could
   be either the working directory, C:\WINDOWS\SYSTEM, or a directory
   in the path.

   NOTE: loading a Visual Basic project does not change the working
   directory. The current project directory is not usually searched
   when loading a DLL.

12. Run the Visual Basic application, and click the command buttons to
   execute the FORTRAN subroutines. The results will appear in the
   text window.

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Additional query words: HF1047.EXE kbfile

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Keywords          : kbfile 
Technology        : kbVBSearch kbAudDeveloper kbFortranSearch kbVB300Search kbVB300 kbZNotKeyword3 kbFORTRAN510DOS
Version           : :3.0,5.1

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