Remote debugging of C++ code

Suitable with AXC F x152 with inactive Security Profile only

PLCnext Technology has an integrated GDB server, so you can set up a remote debugging session. Read more about the GDB server if you're new to this tool or interested in the complete functionality of this tool.

Setting up the station for a remote debugging session takes some time, but remote debugging your C++ code on your PLCnext Control will be a very useful feature that's worth the effort. Most effort goes into setting up the debug configuration. Once you finished that for your station, the rest is quite as simple as you perhaps already know it as an experienced developer. 

Restrictions

• For the time being, a remote debugging procedure cannot be performed on a safety-related controller due to untouchable safety tasks.
• Remote debugging can be done on AXC F x152 with inactive Security Profile only.

Step-by-step instructions

Using the Visual Studio® IDE

See the regarding Maker's Blog article in the PLCnext Community.

Using the Eclipse® IDE

Used in the following description:

• Firmware 2019.x of the AXC F 2152.
• Phoenix Contact Eclipse® Add-in 2020.0 LTS
• Eclipse® 2019-9

Newer versions might differ visually but the procedure is still the same.

Prerequisites

• The task watchdogs must be deactivated (0 ms) during the debug session.
• The shared library must be created in Debug build mode.
• The shared library (.so file) on the host system (Eclipse workspace) and on the PLCnext Control target must be the same.
• The overall performance between steps can take a few seconds.
• For some steps you'll need root or admin user privileges (as admin user, use the sudo precommand).

Debug configuration

1. Make sure to meet the prerequisites regarding the Eclipse versions that these instruction are based on.
2. Open your C++ program in the Eclipse IDE and start the build configuration by the Set Active → Debug all targets menu:
   
3. Start the debug configuration by the Run → Debug Configurations... menu:
   
4. Create a C/C++ Remote Application by double-clicking the list item:
   
5. On the Main tab that shows up in the right section of the dialog box,
   1. insert the path to the C/C++ application executable, e.g.:
      FW_SVN_XXXX\SDK\sysroots\cortexa9t2hf-neon-pxc-linux-gnueabi\usr\bin\Arp.System.Application
   2. Set the "Build Configuration" drop-down menu
      to Debug (in Eclipse Neon):
      
      to Use Active (in Eclipse Photon):
      
   3. Click the Select other link (same in both Eclipse Neon and Photon).
6. In the Select Preferred Launcher dialog box,
   choose GDB (DSF) Manual Remote Debugging Launcher and close with the OK button:
   
7. Back in the Debug Configuration dialog, switch to the Debugger tab, Main subtab, then proceed:
   1. Make sure to have enabled the checkboxes shown here:
      
   2. As the  GDB debugger, insert the command to execute a specific .bat file and just the file name of the gdb executable, e.g.:
      cmd /c C:\PLCnext\SDKs\AXCF2152\2021.0_Release\environment-setup-cortexa9t2hf-neon-pxc-linux-gnueabi.bat && arm-pxc-linux-gnueabi-gdb.exe
   3. As the GDB command file, create a gdbinit.txt file containing the following handles and add it:

      handle SIGUSR2 nostop noprint 
      handle SIGILL nostop noprint 
      handle SIGSTOP nostop noprint

8. On the Shared Libraries subtab of the Debugger tab, proceed:
   1. Insert the directory of the shared library to debug; usually, the library of an Eclipse® project is saved in the Debug or Debug\lib subdirectory to a program.
      
9. On the Connection subtab of the Debugger tab, proceed:
   1. Insert a host name or IP address of the remote target.
   2. Insert the port on which the GDB server instance is listening.
      
10. Click the Close button. The next step is attaching to the remote GDB server.

Attaching to the remote GDB server

1. Log into a shell session on the remote system.
2. Determine the process ID of PLCnext Technology process:
   1. With firmware 2019.0 LTS to 2019.9, issue this command:
      ps | grep Arp.System
   2. From 2020.0 LTS, issue this command:
      ps aux | grep Arp.System
3. Start the gdbserver and attach it to the desired port, e.g. for port 2345:
   sudo gdbserver :2345 --attach <your process ID here>

 

Setting the breakpoints and starting a debug session

1. Select the newly created debug configuration by means of the "bug" menu:
   
2. It might happen that warnings or errors are displayed after starting the debug session.
   1. Warnings in Eclipse® Neon:
      Prevent that by checking Always launch without asking  in the dialog box:
      
   2. Warning in Eclipse® Photon:
      Prevent that by checking Remember my decision in the dialog box:
      
   3. Wait for the the Eclipse® debug view to appear.
3. Add breakpoints and step through your code:
   

 For descriptions to all actions in this environment, please refer to the Eclipse Neon Online Help or the Eclipse Photon Online Help.

 

 

 

• Published/reviewed: 2026-06-11  ✿  Revision 095 •