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Q148643: PRB: Error: Too Many Files Open

Article: Q148643
Product(s): Microsoft FoxPro
Version(s): 3.00 3.00b
Operating System(s): 
Keyword(s): kberrmsg
Last Modified: 19-AUG-1999

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b 
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SYMPTOMS
========

You may receive the following error if Visual FoxPro reaches its file handle
limit of 255:

  Program Error
  Too many files open.

This error can occur when you are close to the limit of 255 files being opened.
The maximum number of files that can be opened in Visual FoxPro is 255, but the
error can occur before 255 because Visual FoxPro opens certain files upon
startup that use some of the file handles.

RESOLUTION
==========

To prevent the error from occurring, do not open that many files. If the number
of files that are being opened is close to the 255 file limit, open and close
files as necessary. To track how many files are open at any given time, create a
variable that can store the number of files that already have been opened. For
example, if you are opening a database container and one table that has a memo
field and an index, 6 files have been opened at this time. They are the DBC,
DCT, and DCX files of the database container, and the DBF, CDX, and FPT files of
the table. By adding and subtracting the number of files that are opened and
closed to the variable each time, you can evaluate when to close any database
containers and tables that are not in use so the error will not occur.

NOTE: This error does not occur as quickly in Visual FoxPro 5.0 because it has
been designed to open as many files as the operating system allows instead of
the 255 file limit currently in Visual FoxPro 3.0.

STATUS
======

This behavior is by design. Visual FoxPro 3.0 can only open a maximum of 255
files.

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

Steps to Reproduce Behavior
---------------------------

Run the following code sample to demonstrate this behavior:

     FOR i = 1 TO 255
      = INKEY(.001)   && Gives create cursor time to keep up
      SELECT (i)
      CREATE CURSOR ("T" + SUBSTR(SYS(2015), 3, 7)) (xyz c(10))
      WAIT WINDOW STR(i) + STR(SELECT()) NOWAIT
     NEXT

When you run this code in a program (.prg) file, watch the Wait Window. Note that
the number count stops and the error occurs around 245 to 250. The exact number
in the display (Wait window) may be different depending on how many files Visual
FoxPro has open when you run the code sample.

Additional query words: VFoxWin

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Keywords          : kberrmsg 
Technology        : kbVFPsearch kbAudDeveloper kbVFP300 kbVFP300b
Version           : 3.00 3.00b

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