DOCUMENT:Q150132  02-NOV-1999  [fortran]
TITLE   :PRB: Undefined Pointer Assignment Causes Application Error
PRODUCT :Microsoft Fortran Compiler
PROD/VER::4.0
OPER/SYS:
KEYWORDS:kbFortranPS kbLangFortrankbbuglist

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

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

SYMPTOMS
========

Attempting to assign a pointer result to an undefined pointer causes one of the
following application errors at run time:

Under Windows NT version 3.51:

   The instruction at "0x00000000" referenced memory at "0x 00000000".
   The memory could not be "written".

Under Windows 95:

   This program has performed an illegal operation and will be shut down.
   If the problem persists, contact the program vendor.

   Details:

   <program> caused an invalid page fault in module <filename.exe> at
   0137:00401022

CAUSE
=====

The pointer variable is undefined at the time of assignment.

RESOLUTION
==========

The pointer must be defined by either a pointer assignment or an allocate
statement.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. We are researching this problem and will post new
information here in the Microsoft Knowledge Base as it becomes available.

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

Sample Code to Illustrate Problem
---------------------------------

   ! Compile options needed: none

         integer, target :: i = 1
         integer, pointer :: p
   ! comment the following line for work-around
         p = i        ! undefined pointer
   ! uncomment the following line for work-around
   !      p => i      ! definition and assignment
         print *, p
         end

Additional query words: 4.00

======================================================================
Keywords          : kbFortranPS kbLangFortran kbbuglist
Technology        : kbAudDeveloper kbPTProdChange kbFortranSearch kbFORTRANPower400NT
Version           : :4.0

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

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