C/C++ Watchpoints with Eclipse Kepler

In “Watchpoints: Data Breakpoints” I used the Eclipse based CodeWarrior to set breakpoints so the debugger stops when my application is writing or reading a certain memory location. That CodeWarrior is based on an earlier Eclipse version, and things are different in Eclipse Kepler and not so easy to find. So here is how I can use watchpoints in Eclipse Kepler:

Watchpoints in Breakpoint View

Watchpoints in Breakpoint View

While you technically *could* set a watchpoint on a local variable, it really only makes sense for a global variable (or to a global memory address). The easiest way in Eclipse Kepler is to use the Outline View and to use the ‘Toggle Watchpoint’ context menu:

Outline View to Set a Watchpoint

Outline View to Set a Watchpoint

💡 If the menu is grayed out, then your variable is not really a global variable?

In the dialog I can configure the watchpoint:

Properties for C C++ Watchpoint

Properties for C/C++ Watchpoint

It is then listed in the Breakpoints view:

Watchpoint in the breakoints view

Watchpoint in the breakoints view

It is possible to set a watchpoint for an address too: instead of using a variable name, use an immediate number for the address:

Using a Watchpoint on an Address

Using a Watchpoint on an Address

Another (hidden) way is to use watchpoints directly in the Breakpoints view using that small triangle menu:

Adding Watchpoints from Breakpoints View

Adding Watchpoints from Breakpoints View

To trigger a stop only if the variable has a certain value, I can add a condition like below:

Watchpoint condition

Watchpoint condition

This will halt the target whenever the value of that globalVariable changes to 50.

Summary

Using watchpoints is a very powerful way to debug an application, as I can stop the execution on memory read/write accesses. Watchpoint support is rather hidden in Eclipse Kepler, but knowing that it exists and where watchpoints can be enabled can help :-).

Happy Watching 🙂

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3 thoughts on “C/C++ Watchpoints with Eclipse Kepler

    • I don’t have much more tips about this. At least not in Eclipse Kepler, as somehow many watchpoint features seem to be broken (conditions seem not to work properly). Not sure why…

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  1. Pingback: Tutorial: Catching Rogue Memory Accesses with Eclipse and GDB Watchpoints | MCU on Eclipse

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