6.9.1 Using breakpoints

Breakpoints will cause a running program to stop when the execution reaches the line where the breakpoint was set. At that moment, control is returned to the IDE, and it is possible to continue execution.

To set a breakpoint on the current source line, use the ”Debug—Breakpoint” menu entry, or press Ctrl-F8.

A list of current breakpoints can be obtained through the ”Debug—Breakpoint list” menu. The breakpoint list window is shown in figure (6.11).

In the breakpoint list window, the following things can be done:

New

Shows the breakpoint property dialog where the properties for a new breakpoint can be entered.

Edit

Shows the breakpoint property dialog where the properties of the highlighted breakpoint can be changed.

Delete

Deletes the highlighted breakpoint.

The dialog can be closed with the ’Close’ button. The breakpoint properties dialog is shown in figure (6.12)

The following properties can be set:

Type

Set the type of the breakpoint. The following types of breakpoints exist:

function

Function breakpoint. The program will stop when the function with the given name is reached.

file-line

Source line breakpoint. The program will stop when the source file with given name and line is reached.

watch

Expression breakpoint. An expression may be entered, and the program will stop as soon as the expression changes.

awatch

(access watch) Expression breakpoint. An expression that references a memory location may be entered, and the program will stop as soon as the memory indicated by the expression is accessed.

Address

stop as soon as an address is reached.

rwatch

(read watch) Expression breakpoint. An expression that references a memory location may be entered, and the program will stop as soon as the memory indicated by the expression is read.

Name

Name of the function or file where to stop.

Conditions

Here an expression can be entered which must evaluate to True for the program to stop at the breakpoint. The expressions that can be entered must be valid GDB expressions.

Line

Line number in the file where to stop. Only for breakpoints of type file-line.

Ignore count

The number of times the breakpoint will be ignored before the program stops.

Remark:

1. Because the IDE uses GDB to do its debugging, it is necessary to enter all expressions in uppercase.
2. Expressions that reference memory locations should be no longer than 16 bytes on linux or go32v2 on an Intel processor, since the Intel processor’s debug registers are used to monitor these locations.
3. Memory location watches will not function on Win32 unless a special patch is applied.