Visual Basic 6 provides a set of predefined
symbolic constants that you can use anywhere in your program.
They’re useful because the constant name, which always starts with
the letters vb, is descriptive of what the constant is. This article
takes a look at a few of the more useful constants.

The constant I use most often is vbCrLf, which
is a combination of a carriage return and a line feed. In other
words, it starts a new line when you’re outputting text. For
example, you can break Message Box text over two or more lines when
you have a long message to display:

MessageBox “This is a long message that should be
broken over
” & vbCrLf & _
    “two lines to prevent the message box from
being too wide.”

If you have need for a carriage return or a
line feed alone, you can use vbCr and vbLf.

The constant vbNullChar is the character with
the value 0; it’s equivalent to Chr(0). It’s useful in various
situations such as calling external procedures that use C calling
conventions, in which strings must be terminated with a null
character.

The constant vbNullString represents a string
with the value 0. This isn’t the same as vbNullChar or an empty
string (“”). It too is used for calling external procedures such as
those in the Windows API.

vbObjectError represents the highest error code
used by VB. When you’re defining your own errors, you should always
use values greater than this. For example:

Err.Raise vbObjectError + 500

Finally, two text-related constants are vbTab
for the tab character, and vbBackspace for the backspace
character.

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