Knowledge Base

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

Article ID: 106729

Article Last Modified on 10/17/2003

Microsoft FORTRAN PowerStation 1.0 Standard Edition
Microsoft Fortran PowerStation 1.0a for MS-DOS
Microsoft FORTRAN PowerStation 32

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

Additional query words: 1.00 4.0 gpf gp-fault

Keywords: kbbug kbfix KB106729