5.3 Setting Line Breakpoints
A breakpoint is a point in a program that
interrupts the running of the program. When stopped at
a breakpoint you can display or change the
value of variables, view the call stack and perform other debug tasks.
This lesson will describe two ways of setting
line breakpoints.
You can only set line breakpoints at executable lines. All executable lines
are displayed in blue.
Using the Prefix Area of the Source pane
The easiest way to set a breakpoint is to
double-click in the prefix area of the Source
pane.
Follow these steps:
- Position your mouse pointer over the prefix
area (left margin) of line 10.
- Double-click with the left mouse button.
A red icon now marks the line, indicating
that a breakpoint is set. You can also right-click
and select Set Breakpoint.

Setting Breakpoints from the Breakpoints menu
You can also use the Breakpoints menu to set breakpoints in your source.
Follow these steps:
-
Ensure that the Breakpoints tab is selected. The Breakpoints menu is added to the debugger's main menu.

- In the prefix area of the Source pane, click at line 47. The cursor in the Source pane moves to
line 47.
- Select Set Line
from the Breakpoints menu. The Line breakpoint window appears with Program, Module,
and Line set and default values for Thread and Frequency.

-
Click OK.
In the prefix area of the Source pane, line 47 is now marked with red icon, indicating that a breakpoint is set.
Click on
to indicate that you have completed these steps.