Debugger Modes of Operation

The debugger plugin runs in different operating modes depending on where and how the process is started and run. Some of the modes are only available for a particular operating system or platform.

You can launch the debugger in the following modes:

• Plain to debug locally started applications, such as a Qt based GUI application.
• Terminal to debug locally started processes that need a console, typically without a GUI.
• Attach to debug local processes started outside Qt Creator.
• Remote to debug a process running on a different machine.
• Core to debug crashed processes on Unix.
• Post-mortem to debug crashed processes on Windows.
• TRK to debug processes running on a Symbian device.

Note: Debugging QML and JavaScript is supported only in plain mode.

When you click the Start Debugging button, the debugger is launched in the appropriate operating mode (plain, terminal, or TRK), based on the build and run settings for the active project. Select Debug menu options to launch the debugger in the other modes.

Plain Mode

To launch the debugger in the plain mode, click the Start Debugging button for the active project, or choose Debug > Start Debugging > Start and Debug External Application... and specify an executable.

Terminal Mode

To launch the debugger in the terminal mode, select Projects > Run Settings and select the Run in terminal check box. Then click the Start Debugging button for the active project.

Attach Mode

To launch the debugger in the attach mode, select Debug > Start Debugging > Attach to Running External Application..., and then select a process by its name or process ID to attach to.

Remote Mode

The remote mode uses a gdbserver daemon that runs on the remote machine.

To launch the debugger in the remote mode, select Debug > Start Debugging > Start and Attach to Remote Application....

Core Mode

The core mode is available only in Unix. It debugs crashed processes using the core files (crash dumps) that are generated if the setting is enabled in the shell.

To enable the dumping of core files, enter the following command in the shell from which the application will be launched:

 ulimit -c unlimited

To launch the debugger in the core mode, select Debug > Start Debugging > Attach to Core....

Post-Mortem Mode

The post-mortem mode is available only on Windows, if you have installed the debugging tools for Windows.

The Qt Creator installation program asks you whether you want to register Qt Creator as a post-mortem debugger. To change the setting, select Tools > Options... > Debugger > Common > Use Creator for post-mortem debugging.

You can launch the debugger in the post-mortem mode if an application crashes on Windows. Click the Debug in Qt Creator button in the error message that is displayed by the Windows operating system.

TRK Mode

The TRK mode is a special mode available only for Symbian. It debugs processes running on a Symbian device using the App TRK application that runs on the device.

To launch the debugger in the TRK mode, open the project, select Symbian as the target, and click the Start Debugging button.

For more information on setting up Symbian projects, see Setting Up Development Environment for Symbian.