FIX: EOF and BACKSPACE Cause GP Fault When the Unit Isn't Open (106729)

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 Q106729

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

Modification Type:	Major	Last Reviewed:	10/17/2003
Keywords:	kbbug kbfix KB106729