DOCUMENT:Q163229  02-APR-1997  [vbwin]
TITLE   :HOWTO: Use Optional Arguments in Intrinsic Data Types
PRODUCT :Microsoft Visual Basic for Windows
PROD/VER:5.0
OPER/SYS:WINDOWS
KEYWORDS:kbusage vb5all vb5howto VBKBInfo_VBKBVB kbhowto

======================================================================
---------------------------------------------------------------------
The information in this article applies to:

 - Microsoft Visual Basic Professional and Enterprise Editions for
   Windows, version 5.0
---------------------------------------------------------------------

SUMMARY
=======

One of the new features of Microsoft Visual Basic 5.0 is the ability to
define Optional arguments for data types other than Variant. These optional
arguments are used in procedures.

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

Microsoft Visual Basic allows optional arguments for the following data
types:

   Data type
   ---------
   Currency
   Double
   Integer
   Long
   Single
   String
   Object

The following conditions and notes should be considered:

1. The Optional argument must be capable of being assigned a default value.
   When a procedure that has Optional arguments is called, Microsoft Visual
   Basic 5.0 assigns all arguments that were not included with a default
   value. Thus, an Optional array is not possible.

2. Optional arguments of user-defined data types are not supported.
   Microsoft Visual Basic 5.0 only supports Optional arguments of intrinsic
   data types.

3. Optional arguments that are of intrinsic data types always return False
   when used with the IsMissing function. This occurs because the IsMissing
   function is explicitly designed for un-initialized Variant data types.
   Because an intrinsic Optional argument always gets its default value if
   not passed to the procedure, it is never missing.

4. Applications written with earlier versions of Visual Basic for
   Applications will ignore the Optional modifier, and thus require the
   argument(s). A good example of this is Microsoft Access for Windows 95.

REFERENCES
==========

Microsoft Visual Basic Online Help

Additional query words: simple data types nonvariant
======================================================================
Keywords            : kbusage vb5all vb5howto VBKBInfo_VBKBVB kbhowto
Version             : 5.0
Platform            : WINDOWS
Issue type          : kbhowto

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.  MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  IN NO
EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR
ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.  SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 1997.