HOWTO: Use an Ampersand (&) to Suppress Sign Extension

Last reviewed: March 20, 1997
Article ID: Q138520

The information in this article applies to:

Microsoft Visual Basic Control Creation, Learning, Professional, and Enterprise Editions for Windows, version 5.0
Standard, Professional, and Enterprise Editions of Microsoft Visual Basic, 16-bit and 32-bit, for Windows, version 4.0

SUMMARY

Adding an ampersand (&) character to the end of a Hexadecimal number will ensure that it is not sign extended. This can be useful when an unsigned constant must be passed to a routine and the magnitude of the constant is greater than or equal to 32,768 (&H8000 in Hexadecimal). If the ampersand is not placed on the end of the constants, Visual Basic assumes that the numbers are sign extended.

MORE INFORMATION

The following example illustrates the effect of an ampersand on a Hexadecimal constant:

Start a new project in Visual Basic. In the default form (Form1), place the following code in the Click event for the form:

      Private Sub Form_Click()
         Dim j As Long
         j = &H8000
         Debug.Print j
         j = &H8000&
         Debug.Print j
      End Sub

Run the code by pressing the F5 key. The Debug window shows the output as -32,768 followed by 32,768 indicating that the ampersand does suppress the sign.

Keywords : kbprg vb4all vb4win vb5all vb5howto VBKBProgramming VBKBVBA kbhowto
Version : 4.0 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.

Last reviewed: March 20, 1997
© 1998 Microsoft Corporation. All rights reserved. Terms of Use.