DOCUMENT:Q112333  24-MAR-2000  [fortran]
TITLE   :FIX: CTRL+Z Is Not End-of-File Marker in PowerStation
PRODUCT :Microsoft Fortran Compiler
PROD/VER::1.0,1.0a
OPER/SYS:
KEYWORDS:kbFortranPS kbLangFortrankbbuglist kbfixlist

======================================================================
-------------------------------------------------------------------------------
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
========

Run-time error F6101 or F6103 (invalid INTEGER or invalid REAL) may be generated
on reading from the last record in a file using Microsoft FORTRAN PowerStation.

CAUSE
=====

The CTRL+Z character is not treated as the true end-of-file marker in MS-DOS or
Windows. This character is interpreted as a nonstandard character by FORTRAN
PowerStation in many circumstances.

RESOLUTION
==========

To resolve this problem, remove the CTRL+Z character from the end of data files.
The function NO_CTRLZ provided below may be used to do this for any file with or
without the CTRL+Z character.

STATUS
======

Microsoft has confirmed this to be a problem in Microsoft FORTRAN PowerStation
32 version 1.0 and 1.0a for MS-DOS and version 1.0 for Windows NT. This problem
was corrected in FORTRAN PowerStation 32, version 4.0.

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

To demonstrate the problem:

1. Build MAKEDATA.FOR and READDATA.FOR (no options are needed).

2. Run MAKEDATA to create a data file ending in a CTRL+Z character.

3. Run READDATA to generate the error:

   run-time error F6101: READ(z-test.dat)
   - invalid INTEGER

4. To fix the data file, build STRIP:

         FL32 strip.for no_ctrlz.for

5. Run STRIP (which uses NO_CTRLZ to remove the CTRL+Z):

         STRIP z-test.dat

6. Run READDATA again (no error will be generated).

Sample Code MAKEDATA.FOR
------------------------

   C Compile options needed: None
         open(10, file='z-test.dat',form='BINARY')
         write(10) '1234', char(26)
         end

Sample Code READDATA.FOR
------------------------

   C Compile options needed: None

         open(10,file='z-test.dat')
         do i=1,20
            read(10,*,end=9) k
            print *, k
         enddo

      9  end

Sample Code STRIP.FOR
---------------------

   C Compile options needed: None
   C To build it use: "FL32 STRIP.FOR NO_CTRLZ.FOR"
         include 'flib.fi'
         include 'flib.fd'

         character *40 filename
         integer*2 i

         if (NARGS() .gt. 1) then
           call getarg(1, filename, i)
           i = no_ctrlz(filename)
           if (i .ne. 0) then
             print *, 'Could not open the file: ', filename
           end if
         end if

         end

Sample Code NO_CTRLZ.FOR
------------------------

   C Compile options needed: None
   c     NO_CTRLZ removes the last character in a file if it is CTRL+Z
   c
   c     Returns 1 if there are problems, otherwise 0.
   c

         integer function no_ctrlz(filename)
         character c, filename*(*)
         logical exist

         inquire(file=filename(:len_trim(filename)),EXIST=exist)
         if (.not. exist) then
           no_ctrlz = 1
           return
         end if

         open(10,file=filename(:len_trim(filename)),access='APPEND',
        +  form='BINARY',recl=1)

   c     Check if the last character is CTRL+Z
         backspace(10)
         read(10) c
         if (ichar(c) .ne. 26) then
           no_ctrlz = 0 !No error, just don't need to do anything
           return
         end if

   c     Backup, and then rewrite the next to last character to reset
   c     the true end-of-file marker.
         backspace(10)
         backspace(10)
         read(10) c
         backspace(10)
         write(10) c

         close(10)

         no_ctrlz = 0  !COMPLETED SUCCESSFULLY

         end

Additional Reference Words: 1.00 ctrl-z

Additional query words:

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

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

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