There are three different types of errors you can encounter in your applications: compile-time errors, runtime errors, and logic errors.
- Compile-time errors occur during the construction of your application. These errors consist mostly of syntax mistakes, variable scoping problems, or data typing problems. In VBA, these types of errors are caught by the development environment. When you enter an incorrect line of code, the line is highlighted and an error message appears telling you the problem. Compile-time errors must be corrected before the application can run.
- Runtime errors are a little more difficult to find and correct. They occur during the execution of your code, and often involve receiving information from the user. For example, if your application requires the user to enter the name of a drawing and the user enters a name for a drawing that didn't exist, a runtime error occurs. To handle runtime errors effectively, you must predict what kinds of problems could happen, trap them, and then write code to handle these situations.
- Logic errors are the most difficult to find and correct. Symptoms of logic errors include situations in which there are no compile-time errors and no runtime errors, but the outcome of your program is still incorrect. This is what programmers refer to as a bug—and a bug can be very easy or very difficult to track down.
Information on finding and correcting all three types of errors can be found in documentation for your development environment. AutoCAD-specific errors fall into the runtime error category, so these types of errors will be covered more fully in this documentation.