Use Debug Alert (-debugalert) to access ABL and .NET stack trace information during a session. Its primary use is for error alert boxes, so you can determine where an error occurred in your code.

When an unhandled ABL error or .NET Exception occurs in an interactive session for any ABL client, the AVM displays an Error message box. With -debugalert, the message box also includes a Help button, which when pressed, produces a Stack Trace dialog box containing ABL and .NET stack trace information. If the error was generated by throwing an error object from the ABL code and the Error Stack (-errorstack) startup parameter is used, or the ERROR-STACK-TRACE attribute on the SESSION system handle is set to TRUE, then the stack trace also includes the contents of the CallStack property for the unhandled error. The ABL and the .NET stack traces are also written to the client log when the Client Logging (-clientlog) startup parameter is specified. The top of the stack (most recent call) is displayed at the top of the trace listing.

To retrieve or set the value of this parameter at runtime, you can use the DEBUG-ALERT attribute of the SESSION system handle. The advantage of setting the DEBUG-ALERT attribute is that its value can be modified during a client session. For more information on the DEBUG-ALERT attribute or the SESSION system handle, see ABL Reference.