MS-DOS Error 24 ("Too Many Files Open") Loading Add-in (.WLL)

• Microsoft Word for Windows, version 6.0

SYMPTOMS

When you load an add-in program (.WLL file) that opens a file in Word for Windows, the following MS-DOS error message may occur:

   Error 24: Too many files open

CAUSE

An add-in program quickly exhausts file handles (which results in the above MS-DOS error message) if you created the add-in using run-time C programming language file routines. This happens because when you load an add-in program created using run-time C routines, Word does not execute the initial run-time C startup code, so any routines that require statics loaded by this code do not run correctly. This is a design feature of Word.

RESOLUTION

You must create your add-in programs using standard Microsoft Windows File Open and file manipulation routines instead of run-time C routines. For information about creating add-ins and .WLL files for Word, see Appendix C of the "Microsoft Word Developer's Kit."

REFERENCES

"Microsoft Word User's Guide," version 6.0, Chapter 31, "Customizing and Optimizing Word," "Using Add-ins with Word" section

"Microsoft Word Developer's Kit," version 6.0, Microsoft Press, 1993, Appendix C, pages 929-950