How do I Set a Data Breakpoint (a Watchpoint)?

Applies to: Serenji 2.0 onwards

Data breakpoints, known as watchpoints in some other debuggers, are set as follows:

1. On the Breakpoints pane, select the Data tab.
2. Double-click on an empty cell under the Expression column (or press Enter on your keyboard when the row is highlighted).
3. Type in the variable or expression you wish to monitor (eg dat or $TR(txt," ")=""). Press Enter to enter it (or click away from the editing cell). The Value column is display-only (hence the gray background) and will show what the expression currently evaluates as. If you don't want the breakpoint to fire whenever a variable in the expression is created, KILLed or NEWed, put the variable inside a $GET in the Expression cell (eg $G(dat) or $TR($G(txt)," ")="").
4. Click on Go to run the application. (No fast-forwarding is available when using data breakpoints, because Serenji has to check the value of the expression after each line of code is executed.)

When the value of your expression (eg $G(dat)) changes, the breakpoint fires so you are taken into debug mode at the start of the next command. The Previous column (also display-only) shows what value the expression had before the change, and the Value column shows the new value.

Last reviewed: Nov 15, 2004

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Copyright 1997, 2005 George James Software.