System Debugger

Introduction

You can interrupt processing and enter the System Debugger by pressing the BREAK key. This will not work if this function has been inhibited from within the currently executing program or command.

Normally, you would enter the System Debugger only at the request of your local support representative. Occasionally, a process may unexpectedly enter the System Debugger.

Interrupting Execution

When you press the BREAK key, Reality displays

I: $ = x,d
rdb ->

where x and d describe the software location of the interruption.

If you press the BREAK key and Reality displays a message in the format:

I xxxx n
*

where n is a number, you have interrupted a DataBasic program (named xxxx) and have entered the DataBasic Debugger.

Loss of Data

Breaking into a program can cause the system to lose the last line of characters you typed; therefore, you should check the last transaction (for example, a change, addition, or deletion) that the user entered to make sure it is complete.

Aborts

Reality may enter the System Debugger as the result of either software or hardware problems. If the user who encounters the problem does not have the System Debugger enabled in his security profile he is limited to using two commands:

• Typing END  returns the process to TCL.
• Typing OFF  logs off from Reality.

The nature of the problem that caused the System Debugger to be entered may render both of these commands inoperative. In these circumstances the EXIT command can be used to cause an immediate exit but note that this will leave an inconsistent state to be cleared up by the database daemon.

Commands

Entering ?  at the rdb->  prompt results in display of the available commands:

Command	More Help	Description
??		Extra Rdb functions and descriptions.
!cmd	?cmd	Execute host command line.
/address		Display data area.
< filename	?<	Input and execute rdb commands from a file.
atd	?atd	Disable tandem. Once disabled in this way, tandem cannot subsequently be re-enabled for this user session.
ate	?ate	Enable tandem.
ata	?ata	Disable tandem, but allow it to be re-enabled with the ate command.
b address condition address	?b	Set breakpoint.
c	?c	Continue execution.
d	?d	Display all breakpoints and trace variables.
e nnn	?e	Set execution step count to nnn.
end	?end	Return to TCL.
exit	?exit	Return to shell.
f	?f	Trace Frame execution.
k [n || *]	?k	Kill breakpoint n; * kills all.
n nnn	?n	Skip nnn breakpoints.
off	?off	Logoff from Reality.
p {filename}	?p	Set psym to filename.
rbs portNumber	?rbs	Display the current state of the DataBasic stack for the specified port. Similar to running realprof with the –g option (see Using the DataBasic Profiler for details).
rs	?rs	Display return stack as frame, binary offset.
t address	?t	Set a trace variable.
u [n || *]	?u	Undo trace n; * undoes all.
z options	?z	Source display control functions.
? address		Show different address format.