INF: Using the Undo Feature with Breakpoints

ID Number: Q75603

3.00 3.10 3.11 3.14 | 3.00 3.10 3.11 3.12 3.50

MS-DOS | OS/2

Summary:

Using the Run Undo feature after running to a breakpoint will cause

the Microsoft CodeView Debugger versions 3.0, 3.1, 3.11, 3.12, 3.14,

and 3.5 to replay the debug history up to the previous CodeView

command, rather than up to the last executable instruction before the

breakpoint.

More Information:

With the History feature turned on, if a breakpoint is set and the

program being debugged is executed up to that breakpoint by pressing

the F5 function key or choosing Go, CodeView records the program

execution to the breakpoint as one step in the debug history. Even

though multiple program instructions may be executed during the run,

the entire process is treated as one CodeView command.

The Run Animate and Run Undo features can be used together to allow a

program to be executed up to a breakpoint, and then traced back one

executable instruction at a time.

The following steps outline this process:

1. From the Watch menu, choose Set Breakpoint to set a breakpoint at

the desired location in the program.

2. From the Run menu, choose History On to turn on the history

recording feature.

3. From the Run menu, choose Animate to have CodeView trace the program

execution up to the breakpoint. The trace speed can be set by choosing

Trace Speed from the Options menu.

4. Last, from the Run menu, choose Undo to have CodeView replay the debug

history up to the instruction before the breakpoint. This step can be

repeated multiple times to effectively allow CodeView to "back-up" one

instruction at a time from the breakpoint.