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Q138520: HOWTO: Use an Ampersand (&) to Suppress Sign Extension

Article: Q138520
Product(s): Microsoft Visual Basic for Windows
Version(s): WINDOWS:4.0,5.0
Operating System(s): 
Keyword(s): kbprogramming kbVBp400 kbVBp500 kbhowto
Last Modified: 11-JAN-2001

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The information in this article applies to:

- Microsoft Visual Basic Control Creation Edition for Windows, version 5.0 
- Microsoft Visual Basic Learning Edition for Windows, version 5.0 
- Microsoft Visual Basic Professional Edition for Windows, version 5.0 
- Microsoft Visual Basic Enterprise Edition for Windows, version 5.0 
- Microsoft Visual Basic Standard Edition, 32-bit, for Windows, version 4.0 
- Microsoft Visual Basic Professional Edition, 16-bit, for Windows, version 4.0 
- Microsoft Visual Basic Professional Edition, 32-bit, for Windows, version 4.0 
- Microsoft Visual Basic Enterprise Edition, 16-bit, for Windows, version 4.0 
- Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows, version 4.0 
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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:

1. 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

2. 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.

Additional query words:

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Keywords          : kbprogramming kbVBp400 kbVBp500 kbhowto 
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVBA500Search kbVBA500 kbVB500 kbVB400Search kbVB400 kbZNotKeyword3 kbVB16bitSearch
Version           : WINDOWS:4.0,5.0
Issue type        : kbhowto

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