CLion 2018.1 Help


General debugging steps

  1. Configure the debugger options
  2. Choose the desired CMake profile.
  3. Define a run/debug configuration for the application to be debugged.
  4. Create breakpoints in the source code.
  5. Launch a debugging session.
  6. Pause or resume the debugging session as required.
  7. During the debugger session, step through the breakpoints, evaluate expressions, change values on-the-fly examine suspended program, set watches and watchpoints.

After you've started a debug session, the debug icon that marks the Debug tool window toggles to debug active to indicate that the debug process is active.


After you have configured a run configuration for your project, you can launch it in debug mode by pressing Shift+F9.

In the Debug tool window you can see the list of frames and threads with their states, variables and watches. When you select a frame, you see the variables corresponding to the selected frame.

Useful debugger shortcuts


Breakpoint details and condition

If you want to change details of a breakpoint, press Ctrl+Shift+F8. Here you can specify the breakpoint conditions.


If you have any instance marked with a label, you can use it in the condition expression as well:

breakpointProperties label

To see all breakpoints in the project (with more advanced settings), press the same shortcut Ctrl+Shift+F8 again.

Action breakpoints

Another action might be useful if you want to evaluate something at a particular line of code without actually making a stop. You can do that by using the Action breakpoint. To create one, just click on the gutter while holding Shift.

action breakpoint

Temporary breakpoints

To create a breakpoint that stops only once, click the left gutter while holding Shift+Alt.

temporary breakpoint

Refer to the section Breakpoint types for details.

Disable breakpoints

It's also useful to know that any breakpoint can be quickly disabled by clicking on the gutter while holding Alt.

quick disable breakpoints

Refer to the section Enabling, Disabling and Removing Breakpoints for details.

Debugger session

Drop frame

In case you want to “go back in time” while debugging you can do it via Drop Frame action. This is a great help if you mistakenly stepped too far. This will not revert the global state of your application but at least will get you back by stack of frames.

drop frame

The icon frames drop frame is described in the Debug tool window reference.

Run to cursor

Sometimes you need to resume the program and stop at another line of code, without adding another breakpoint. Easy: just press Alt+F9.

run to cursor

The icon frames run to cursor is described in the toolbar reference of the Debug tool window.

Mark instance

If you want a particular instance to be always recognized while debugging, you can mark it with a colored label via F11 or the context menu in the Variables and Watches tabs.

mark object

The next time this instance appears in Watches, Variables or Evaluate expression, you will see the label:

mark object1

Evaluate expression

While in debug mode, you can evaluate any expression by pressing Alt+F8.

evaluate expression1

This tool provides code completion just as in the editor so it’s very easy to enter any expression:

evaluate expression2

If you have any instances marked with labels, code completion will offer you its names so you can evaluate them:

evaluate expression3

Refer to the section Evaluating Expressions for details.

Remote debug

The final thing you definitely should know about debugging in CLion is Remote debug. Remote debug means attaching debugger to a process which is already running on a specific port on your or any other’s host. This way you can attach the debugger to your application server which is running standalone.

To create a remote configuration, go to Edit configurations and add Remote run configuration. Make sure to specify the correct host and port before you run this configuration.


If you want to change the default debugger settings, choose Debugger in CLion Settings/Preferences.

Last modified: 24 July 2018

See Also