CLion 2018.1 Help

Attaching to Local Process

Attach to local process feature allows you to debug a project which you are developing in CLion, but (for some reasons) are not able to launch directly from your IDE.

In CLion, you can attach to a local process with GDB on Windows/Linux or GDB/LLDB on macOS/Linux for C/C++ applications. When applicable, other languages debuggers (e.g., Python debugger or Swift LLDB) can be used as well.

Prerequisites for Ubuntu users

If you are using CLion on Ubuntu (or probably, on some other Linux distribution), an error message ptrace: Operation not permitted may appear upon your first attempt to attach to a local process. In this case, do one of the following:

  • To disable this restriction temporarily, enter the command:
    echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope
  • To disable this restriction permanently, open the /etc/sysctl.d/10-ptrace.conf file for editing and change the line kernel.yama.ptrace_scope = 1 to kernel.yama.ptrace_scope = 0.
    To apply the changes immediately, enter the above command echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope. Alternatively, run sudo service procps restart or simply restart your system.

You can find more details here.

Attaching to local process

To attach to a local process, follow these general steps:

  1. Launch the process intended for debugging. You can do it from operating system or using the CLion terminal.
  2. To find the process to attach to, do one of the following:
    • On the main menu, choose Run | Attach to Local Process:
      cl attachtoprocess action
    • On the main menu, choose Help | Find Action or press Ctrl+Shift+A. In the list of actions that appears, find the desired action by typing the first letters, and select it:
      cl attachtoprocess findaction
  3. From the list of available processes that appears, select the desired process. Simplify your search by typing the first letters of its name or PID
    cl attachprocess name
    In case there are several debuggers that can be used for the selected process, you can choose among them in the pop-up menu:
    cl attachprocess multdebug
  4. Proceed with debugging the same way as you usually do it in CLion (set breakpoints, step through, pause and resume the process, evaluate expressions, etc.):
    cl debugger variables
  5. When finished, detach the process: select the Run | Stop or click the Stop the process button stop of the Debug Tool Window.
Last modified: 30 May 2018

See Also