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Chapter 6: Trapping Errors and Squashing Bugs
11_046500 ch06.qxp 12/5/06 5:35 PM Page 139

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see library references used in many places in this book. For example, when
you work with the hard drive, you need to add a new library to your applica-
tion. The following section of this chapter describes how to add a reference
to a library. If you don’t include all the library references that your applica-
tion requires, the application displays a run-time error.
Recovering from an error
Recovering from an error is important. Adding recovery code means that you
can count on your program to help you overcome problems with the system
and keep your data safe. You can add two kinds of recovery code to your
program:
Code that recovers before the error happens
Code that recovers after the error happens
It’s always better to detect an error and recover from it before the error actu-
ally happens. You can always recover from a resource error, such as lack of
hard drive space, before the error happens. Likewise, you can always recover
from input errors by making the required checks and asking for the correct
input. The only time you must wait for the error to happen is when you can’t
predict the error, such as a sudden loss of power.
A common run-time error is lack of hard drive space. To add a drive-checking
feature to your program, you need to add a new library to your program. Use
the Tools
➪
References command to display the References dialog box, as
shown in Figure 6-2. Notice that the Microsoft Scripting Runtime check box is
selected. Look for this entry in your dialog box and select it. Click OK. The
new library is ready for use.
Figure 6-2:
Use this
dialog box
to add a
new library
to your
program.
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