PRB: Error: Too Many Files Open (148643)


The information in this article applies to:

  • Microsoft Visual FoxPro for Windows 3.0
  • Microsoft Visual FoxPro for Windows 3.0b
This article was previously published under Q148643

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.
Modification Type:MajorLast Reviewed:9/30/2003
Keywords:kberrmsg KB148643
©2003 Microsoft Corporation. All rights reserved.