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Q106729: FIX: EOF and BACKSPACE Cause GP Fault When the Unit Isn’t Open

Article: Q106729
Product(s): Microsoft Fortran Compiler
Version(s): 1.0,1.0a
Operating System(s): 
Keyword(s): 
Last Modified: 24-MAR-2000

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

- Microsoft FORTRAN PowerStation for MS-DOS, versions 1.0, 1.0a 
- Microsoft Fortran Powerstation 32 for Windows NT, version 1.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

Passing an unopened unit number to the EOF intrinsic function or the BACKSPACE
command generates the run-time error:

FORTRAN PowerStation for MS-DOS
-------------------------------

  DOSXMSF : fatal error DX1020: unhandled exception: General protection fault;

FORTRAN PowerStation 32 for Windows NT
--------------------------------------

  Application Error

  The instruction at "0x0001316e" referenced memory at 0x00000000". The memory
  could not be "read".

CAUSE
=====

The following run-time error should be produced:

  run-time error F6420: EOF()
  - unknown unit number

RESOLUTION
==========

Only use the EOF function and BACKSPACE command on units that are currently
open.

STATUS
======

Microsoft has confirmed this to be a problem in the Microsoft products listed at
the beginning of this article. This problem was fixed in FORTRAN PowerStation,
version 4.0.

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

The following sample code generates a DX1020 error (GPF) when run:

Sample Code
-----------

  C Compile options: None
        logical l
        open(2,file='test.out')
        l = EOF(1)
        end

Additional query words: 1.00 4.0 gpf gp-fault

======================================================================
Keywords          :  
Technology        : kbAudDeveloper kbFortranSearch kbZNotKeyword2 kbZNotKeyword3 kbFORTRANPower32100NT kbFORTRANPower100DOS kbFORTRANPower100aDOS
Version           : :1.0,1.0a
Issue type        : kbbug
Solution Type     : kbfix

=============================================================================

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