Progress
Debugger Guide


Command Panel

The command panel provides an area to enter commands from the keyboard, and to record a history of all commands entered and executed during a debugging session. This command history includes commands entered from the menu bar, button panel, and command files, as well as the command panel itself. Each entered command echoes and scrolls into the panel scrolling area before it executes. The panel also displays the number of commands entered in the command queue and ready to execute.

Panel Components

The command panel provides a different interface in each window system. In Windows, the panel has two components:

In Motif, the panel has three components:

The command panels in Figure 4–1 and Figure 4–2 of the "Window Layout" section show the CONTINUE command typed in the command panel and ready to enter in the command queue.

Command Queue

The Debugger places all commands that you enter in a command queue. This is a typical first-in-first-out (FIFO) input queue. When the Debugger has control with the queue empty, any single command you enter is executed immediately. However, if you enter several commands using a command file or enter commands directly in the Debugger window while your application has control, all commands remain in the command queue until the Debugger is able to execute them. The Commands in Queue field (queue indicator) displays the number of commands in the Debugger command queue at any moment.

NOTE: You can purge the command queue at any time using the break interrupt function from the Debugger window. For more information, see the "Menu Bar" section of this chapter and Running a Debugging Session."

Panel Operation

As each command enters the command queue, the queue indicator increments and the command scrolls up to the bottom of the command history. As the Debugger executes each command, the queue indicator decrements. When the Debugger has executed all commands in the queue, the queue indicator displays 0.

Therefore, if you enter a command in the Debugger window and the queue indicator stays set at 1 or greater, you know that the application you are running is in control, and not the Debugger. The Debugger can begin executing these commands only after your application reaches a breakpoint or returns control to the Debugger when it terminates.

Note that the next command the Debugger executes is located on the nth line from the bottom of the command history, where n is the integer displayed by the queue indicator. For example, suppose the command panel displays the following command history:

break 1000
continue
display variable ExecStatus
display field customer.Name
display field customer.Credit
display variable OrdersTotal 

If the queue indicator is 4, when the Debugger gets control, it will begin by executing the display variable ExecStatus command on the fourth line from the bottom.

For more information on entering commands using the command panel and other components of the Debugger window, see Running a Debugging Session."


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