6.21.1   Breakpoints on Variables

In addition to line-based breakpoints (see section “Program Window”), breakpoints can also be set on variables. Right-click a variable name and select Set/Clear Breakpoint on Variable. Variables with breakpoints are marked with next to their name.

Once a breakpoint has been set on a variable, the program execution stops whenever its value changes. A change of value is detected in the same way the HDevelop operation != works (see section “Comparison Operations”):

• Iconic objects: a value change is triggered if the variable refers to a different object in the database (see also test_equal_obj).
• Tuples: A change of the data type (for example, integer to real) does not necessarily trigger a value change. In the following example the second assignment would not trigger a variable breakpoint on tuple:

  tuple := [1,2,3]
  tuple[1] := 2.0     // 2 == 2.0
  

Using clear_obj does not trigger a variable breakpoint. Use dev_clear_obj instead.

When a breakpoint on a variable triggers, the program execution stops and HDevelop highlights the corresponding variable in the variable window. If the variable is not currently displayed in the selected tab of the variable window, HDevelop switches to the tab Auto (see below).

Information about the event is displayed in the status bar, for example, HDevelop displays both the old and the new value of a tuple.