| SAS Language Reference: Dictionary |
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| Definition: What is Debugging? |
Debugging
is the process of removing logic errors from a program. Unlike syntax errors,
logic errors do not stop a program from running. Instead, they cause the program
to produce unexpected results. For example, if you create a DATA step that
keeps track of inventory, and your program shows that you are out of stock
but your warehouse is full, you have a logic error in your program.
To debug a DATA step, you could
- copy a few lines of the step
into another DATA
step, execute it, and print the results of those statements
- insert PUT statements at selected places in the
DATA step, submit the step, and examine the values that are displayed in the
SAS log.
- use the DATA step debugger.
While the SAS log can help you identify data errors,
the DATA step debugger offers you an easier, interactive way to identify logic
errors, and sometimes data errors, in DATA steps.
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| Definition: The DATA Step Debugger |
The DATA step debugger is
part of base SAS software and consists
of windows and a group of commands. By issuing commands, you can execute DATA
step statements one by one and pause to display the resulting variable values
in a window. By observing the results that are displayed, you can determine
where the logic error lies. Because the debugger is interactive, you can repeat
the process of issuing commands and observing the results as many times as
needed in a single debugging session. To invoke the debugger, add the DEBUG
option to the DATA statement and execute the program.
The DATA step debugger enables you to perform the following
tasks:
- execute statements one by one or in groups
- bypass execution of one or more
statements
- suspend execution at selected statements, either
in each iteration of DATA step statements or on a condition you specify, and
resume execution on command
- monitor the values of selected variables and suspend
execution at the point a value changes
- display the values of variables and assign new
values to them
- display the attributes of variables
- receive help for individual debugger
commands
- assign debugger commands to function keys
- use the macro facility to generate customized
debugger commands.
Copyright 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.
