FIX: Divide by Zero Creates Err with Third-Party Print Drivers

• Microsoft Visual FoxPro for Windows, versions 5.0, 5.0a, 6.0

SYMPTOMS

If certain third-party printer or fax drivers are loaded when one of several commands, which invoke printer driver routines are used, and followed by division by zero, Visual FoxPro 5.0 or 5.0a terminates with the following error:

This program has performed and illegal operation and will be shut down.
If the problem persists, contact the program vendor.

VFP caused an exception 10H in module VFP.EXE at <address>.

A fatal exception 0D has occurred at 0028:c0038f07 in VXD VMCPD(01) + 00002DB. The current application will be terminated.

* Press any key to terminate the current application.
* Press CTRL+ALT+DEL again to restart your computer. You will lose
any unsaved information in all applications.

CAUSE

Visual FoxPro sets the numeric coprocessor to handle exceptions in hardware. The printer driver routines change this numeric coprocessor setting so that coprocessor exception handling takes place in software, but fails to restore the original setting when the printer driver routines have completed. When a subsequent numeric coprocessor exception occurs in Visual FoxPro (division by zero, for instance), the numeric coprocessor expects the exception to be handled in software. Visual FoxPro is not able to do this, and an exception error, crash or hang occurs.

RESOLUTION

Here are three ways you can work around this error:

• Use a printer driver supplied with Windows 95.


-or-


• Disable the numeric coprocessor through Control Panel. Open Control Panel and double-click the System icon. In the System Properties dialog box, select the Device Manager tab. Scroll down the list and expand the System Devices listing. Double-click Numeric Data Processor and select the Settings tab. Make sure the option button "Never use the numeric data processor" is selected.
  
  NOTE: This change may result in the following error messages on reboot:

  A fatal exception 0D has occurred at 0028:c0038f07 in VXD VMCPD(01) + 00002DB. The current application will be terminated. * Press any key to terminate the current application. * Press CTRL+ALT+DEL again to restart your computer. You will lose any unsaved information in all applications.

  If this happens, restart in safe mode.
  
  Enable the numeric coprocessor through the Control Panel. Open Control Panel and double-click the System icon. In the System Properties dialog box, select the Device Manager tab. Scroll down the list and expand the System Devices listing. Double-click Numeric Data Processor and select the Settings tab. Make sure the option button "Always use the numeric data processor" is selected. After restarting the computer, the preceding error is gone; however, either item 1 or item 3 is required to resolve the 10h error.


-or-


• Use the _fpreset function in the Microsoft Visual C++ run-time DLL to reset the numeric coprocessor. This is demonstrated in the following code:




     *-- Code begins here
      DECLARE _fpreset IN msvcrt20.dll
      =_fpreset()
      *-- Code ends here 

This can be implemented within an application by adding this to the beginning of your main program:

   DECLARE _fpreset IN msvcrt20.dll 

The DECLARE statement only needs to be made once. You should use the call to _fpreset() immediately after using any of the following functions or commands:


   GETPRINTER()
   REPORT FORM ... TO PRINTER
   REPORT FORM ... PREVIEW
   SET( "Printer", 2)
   SET( "Printer", 3)
   SET PRINTER TO NAME <printer name>
   SYS(1037) 

You should also call _fpreset() after calling File/Page Setup from the Visual FoxPro menu, or after clicking the "Print One Copy" button on the FoxPro Standard toolbar.

It may also be necessary to add a call to _fpreset() to Dataenvironment BeforeOpenTables and Destroy methods of each report. Under some circumstances, you may also need to add _fpreset() calls to the end of the Load and Destroy methods of forms, especially in, but not limited to, custom forms from which your application does printing.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article.

This bug was corrected in Visual Studio 6.0 Service Pack 3. For more information about Visual Studio service packs, please see the following articles in the Microsoft Knowledge Base:

Q194022 INFO: Visual Studio 6.0 Service Packs, What, Where, Why

Q194295 HOWTO: Tell That Visual Studio 6.0 Service Packs Are Installed

MORE INFORMATION

1. On a Windows 95 computer, install the Hewlett-Packard 6.0 printer driver.
   
   
   
   The Hewlett-Packard 6.0 printer does not have to be physically installed on the computer; just the print driver is needed.



2. Run the following code:
   

   
      *-- Code begins here.
      =GETPRINTER()  && Select the HP6 printer.
      m1 = 9/0 && Any division by zero will work.
      *-- Code ends here. 




3. Alternatively, create a report, add a text field and set the expression to "m1/m2" without the quotes, or set the expression to 9/0 and then, click OK. Next, preview the report.

Additional query words: kbvfp600fix kbdse LaserJet LJ Lexmark

Keywords : kbservicepack kbVFp600 kbVFp600fix kbVS600sp2 kbVS600SP1 kbVS600sp3fix FxprgBrowse FxprintDriver FxtoolRwriter
Version : WINDOWS:5.0,5.0a,6.0
Platform : WINDOWS
Issue type : kbbug