Q149753: How to Determine the Size of a User-Defined Data Type

Article: Q149753
Product(s): Microsoft Fortran Compiler
Version(s): 4.0
Operating System(s): 
Keyword(s): kbcode kbFortranPS kbLangFortran
Last Modified: 03-NOV-1999

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

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

SUMMARY
=======

The Fortran Run-Time Library included with Microsoft Fortran PowerStation
version 4.0 does not include an intrinsic function or subroutine that can return
the number of bytes in use by a single user-defined data type variable. You can,
however, use the LOC() intrinsic function to obtain the starting addresses of
two user-defined data type variables, contiguous in memory, and subtract their
addresses resulting in the number of bytes used by one variable of this type.

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

Do the following to calculate the number of bytes in use by a single user-
defined data type variable:

1. Create a two-element array variable of any user-defined data type.

2. Use the LOC() intrinsic function to obtain the starting memory addresses for
  both user-defined data type array elements.

3. Subtract these addresses from each other. This will yield the number of bytes
  used in memory by this type of user-defined variable.

Sample Code to Illustrate Technique
-----------------------------------

  C Compile options needed: none
        type udt
            integer a
            real b
        end type
        type (udt) myt(2)
        print *, 'Number of bytes used: ', loc(myt(2)) - loc(myt(1))
        end

Program Output
--------------

Number of bytes used: 8

Additional query words: 4.00 kbinf

======================================================================
Keywords          : kbcode kbFortranPS kbLangFortran 
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.

Copyright Microsoft Corporation 1986-2002.