Q104896: FIX: F6100 Reading Maximal Negative Integers

Article: Q104896
Product(s): Microsoft Fortran Compiler
Version(s): 1.0,1.0a
Operating System(s): 
Keyword(s): kberrmsg kbFortranPS kbLangFortran
Last Modified: 24-MAR-2000

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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 
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SYMPTOMS
========

For any integer data type, reading the smallest negative integer of that range
generates the run-time error F6100 indicating that there was an INTEGER overflow
on input.

STATUS
======

Microsoft has confirmed this to be a problem in the Microsoft products listed at
the beginning of this article. This problem was corrected in Microsoft FORTRAN
PowerStation 32, version 4.0.

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

The smallest negative integer for each integer data type is:

  -128 Integer*1
  -32768 Integer*2
  -2147483648 Integer*4

The sample code below generates the 6100 error for all integer types when
compiled with PowerStation, but only generates the 6100 error for integer*4 with
FORTRAN 5.1 and earlier.

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

  C No Compiler options needed
        integer*1 i
        integer*2 j
        integer*4 k
        open(1,file='test.dat')
        do 10 n=3,5
          write(1,*) -2**((2**n-1))
   10   continue

        rewind(1)
        read(1,*,iostat=ierr) i
        if(ierr.eq.6100) then
          print*, 'error reading integer*1 was: ',ierr
        else
          print*, 'integer*1 input: ',i
        end if

        read(1,*,iostat=ierr) j
        if(ierr.eq.6100) then
          print*, 'error reading integer*2 was: ',ierr
        else
          print*, 'integer*2 input: ',j
        end if

        read(1,*,iostat=ierr) k
        if(ierr.eq.6100) then
          print*, 'error reading integer*4 was: ',ierr
        else
          print*, 'integer*4 input: ',k
        end if

        end

Additional query words: 1.00 5.10

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

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