FIX: F6100 Reading Maximal Negative Integers (104896)


The information in this article applies to:

  • Microsoft FORTRAN PowerStation for MS-DOS 1.0
  • Microsoft FORTRAN PowerStation for MS-DOS 1.0a
  • Microsoft Fortran Powerstation 32 for Windows NT 1.0
This article was previously published under Q104896

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
Modification Type:MajorLast Reviewed:10/17/2003
Keywords:kbbug kberrmsg kbfix kbLangFortran KB104896
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