Q65884: How to Pass a BASIC COMMON Block to a FORTRAN 5.00 Subroutine

Article: Q65884
Product(s): See article
Version(s): 7.00 7.10 | 7.00 7.10
Operating System(s): MS-DOS | OS/2
Keyword(s): ENDUSER | SR# S900810-80 H_Fortran B_QuickBas | mspl13_basic
Last Modified: 22-OCT-1990

This article explains how to pass a BASIC COMMON block to a FORTRAN
version 5.00 subroutine.

This information applies to Microsoft QuickBASIC version 4.50, to
Microsoft BASIC Professional Development System (PDS) version 7.00 for
MS-DOS and MS OS/2, and to Microsoft FORTRAN Compiler version 5.00.
This information does not apply to earlier versions of these products
(due to incompatibilities).

To program interlanguage calling between FORTRAN 5.00 and BASIC PDS
version 7.10, you must obtain the following application note from
Microsoft Product Support:

   "How to Link BASIC PDS 7.10 with C 5.10, FORTRAN 5.00, or Pascal
    4.00." (application note number BB0345)

(The FORTRAN 5.00 run-time libraries must be rebuilt as shown in this
application note to be compatible with the BASIC PDS 7.10 run-time
libraries.)

The technique illustrated below shows how to pass a named BASIC COMMON
block to a FORTRAN subroutine. This technique will not work with
unnamed BASIC COMMON blocks. This technique will work only with
FORTRAN version 5.00 because you must use a FORTRAN STRUCTURE...END
STRUCTURE data type, which is not supported in earlier versions of
FORTRAN.

The strategy is to pass the segment and offset of the first variable
in the named BASIC COMMON block as a parameter in the call to the
FORTRAN subroutine. The FORTRAN subroutine should set up a
STRUCTURE...END STRUCTURE type variable with the same format as the
BASIC COMMON block. The FORTRAN subroutine must receive this STRUCTURE
type variable as a formal parameter.

Code Example
------------

Below is the BASIC program BASCOMMN.BAS that sets up the named COMMON
block, initializes the values, and calls the FORTRAN subroutine:

   'BASCOMMN.BAS **********************************************
   DECLARE SUB FORSUB (BYVAL segment%, BYVAL offset%)
   COMMON SHARED /Example/ a%, b&, c!, d#
   CLS
   a% = 10
   b& = 2000
   c! = 30.3
   d# = 40.125
   PRINT
   PRINT "Hit any key to call the FORTRAN subroutine"
   SLEEP
   CALL FORSUB(VARSEG(a%), VARPTR(a%))
   LOCATE 8, 1: PRINT "back in basic"
   END

Below is the FORTRAN program FORCOMMN.FOR, which contains the
subroutine Forub(). It sets up a STRUCTURE type variable similar to
the corresponding named BASIC COMMON block, and prints out the values:

C FORCOMMN.FOR   **********************************************
      SUBROUTINE FORSUB( VAR )
      STRUCTURE /BASCOMMON/
          INTEGER*2 A
          INTEGER*4 B
          REAL*4    C
          DOUBLE PRECISION D
      END STRUCTURE
      RECORD /BASCOMMON/ VAR
      PRINT *, VAR.A
      PRINT *, VAR.B
      PRINT *, VAR.C
      PRINT *, VAR.D
      END

Below is the BASIC code for NEARHEAP.BAS, which allocates near heap
space for the FORTRAN subroutine. If you are working inside the
QuickBASIC QB.EXE or QBX.EXE environment, compile this routine and put
it into a Quick library along with the FORTRAN program. If you are
compiling and linking into an .EXE program, put these lines in the
source code of the BASIC program or in a separate BASIC .OBJ module in
a .LIB library.

   ' NEARHEAP.BAS **********************************************
   DIM Heap%(2048)
   COMMON SHARED /NMALLOC/ Heap%()

Compile the FORTRAN program as follows:

   FL /c /AM FORCOMMN.FOR

To work inside the QuickBASIC 4.50 QB.EXE environment, build the
libraries as follows:

   BC NEARHEAP.BAS;
   LIB FORCOMMN.LIB+NEARHEAP+FORCOMMN;
   LINK /Q FORCOMMN.LIB, FORCOMMN.QLB,,BQLB45.LIB MLIBFER.LIB;

To compile and link from DOS, build the libraries the same way and
compile and link BASCOMMN.BAS as follows:

   BC BASCOMMN;
   LINK /NOE BASCOMMN+FORCOMMN.LIB,,,BRUN45.LIB+MLIBFER.LIB ;

To work inside the BASIC PDS 7.00 QBX.EXE environment, build the
libraries as follows

   BC /Fs/FPi NEARHEAP;
   LIB FORCOMMN.LIB+NEARHEAP+FORCOMMN;
   LINK /Q FORCOMMN.LIB, FORCOMMN.QLB,,QBXQLB.LIB MLIBFER.LIB ;

and compile and link from DOS as follows:

   BC /Fs/FPi BASCOMMN;
   LINK /NOE BASCOMMN+FORCOMMN.LIB,,,BRT70EFR+MLIBFER.LIB ;

The output from the program is as follows:

   Hit any key to call the Fortran subroutine
                10
              2000
             30.300000
             40.125000000000000

   Back in BASIC

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