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  1. When the application runs to read the application installation resource file under /usr/share, why does the reading fail?

    Linglong applications run in a container, and the application data will be mounted to /opt/apps/<appid>/. Only system data will exist in the /usr/share directory, and there will be no application-related data. Therefore, reading directly from /usr/share will fail. Suggested processing: Use the XDG_DATA_DIRS environment variable to read resources, and /opt/apps/<appid>/files/share will exist in this environment variable search path.

  2. The font library file cannot be found when the application is running. Why can the corresponding font library be read when the deb package is installed?

    When the deb package is installed, it will depend on the corresponding font library file. The Linglong package format adopts a self-sufficient packaging format. Except for the basic system library, qt library and dtk library files provided in runtime, do not need to be provided by yourself, other dependent data files need to be provided by yourself. It is recommended to put the corresponding data file under files/share, and use the environment variable XDG_DATA_DIRS to read the path.

  3. What is in the Linglong application runtime? Can you add some library files to it?

    At present, the runtime that Linglong application depends on provides the qt library and the dtk library. Because runtime has a strict size limit, adding additional library files to runtime is currently not allowed.

  4. The application runs in the container. Can a configuration file be created in any path of the container during the running process?

    This is not allowed. The file system in the container is a read-only file system and configuration files are not allowed to be created under arbitrary paths.

  5. Where is app data saved? Where can I find it outside the container?

    Because Linglong applications follow the principle of non-interference, the XDG_DATA_HOME, XDG_CONFIG_HOME, XDG_CACHE_HOME environment variables are defined in the corresponding path of the host machine, ~/.linglong/<appid>/. So the user application data will be saved under this path. When writing data while the application is running, it should also be able to read the corresponding environment variable to write the data. Mutual configuration calls between applications are prohibited.

  6. The application provides the dbus service file, where do I place it? What does the Exec segment write?

    When the application provides the dbus service file, it needs to be placed in the entries/dbus-1/services directory. If Exec executes the binary in the Linglong package, use the --exec option parameter to execute the corresponding binary.

  7. Can the application download files to the $HOME directory by default? I downloaded the file, why can't I find it on the host machine?

    Linglong specification does not allow files and directories to be created in the $HOME directory.

  8. Why does the desktop shortcut icon appear as a gear or blank? How are the icon files placed?

    If the gear shaped icon is displayed, the icon has not been obtained. You need to confirm whether the Icon path name is correct. When the icon is empty, the tryExec field exists. When the command does not exist, it will cause the shortcut to display improperly. Place the application icon in the icons directory. The directory structure should be consistent with the system icons directory structure. The recommended path is icons/hicolor/scalable/apps/org.desktopspec.demo.svg. Use svg format icons. Refer to the icon file format specification. If you use a non-vector format, please place the icon according to the resolution. Note that the desktop file should not write the icon path, but directly write the icon name.

  9. Why do xdg-open and xdg-email that come with the application fail?

    Linglong specially handles xdg-open and xdg-email in runtime, so the application is forbidden to execute the executable file or script of xdg-open and xdg-email that it carries.

  10. Why doesn't the system environment variable used by the application take effect?

    When using environment variables, you need to confirm whether there are corresponding environment variables in the container. If not, you need to contact the Linglong team for processing.

  11. The library files required for the application to run were not found. How can I provide them?

    The resource files that the application needs to use and the library files both need to be provided by the application itself. The library files are placed in the files/lib path.

  12. Where can I choose the application download directory?

    Currently Linglong users can only choose the Desktop, Documents, Downloads, Music, Pictures, Videos, Public, and Templates directories under the user's home directory, and cannot be downloaded to other directories.

  13. Why has the QTWebEngine rendering process crashed when the application is running?

    Due to the system upgrade of glibc, the application fails to use the built-in browser, and the application needs to be re-adapted. A temporary solution is to set the environment variable: export QTWEBENGINE_DISABLE_container=1.

  14. When the application is running, the library cannot be found or the qtwebengine error is reported. What can I do?

    When a qt.conf file exists, you need to configure the correct path in the file or use the QTWEBENGINEPROCESS_PATH, QTWEBENGINERESOURCE_PATH, QT_QPA_PLATFORM_PLUGIN_PATH, and QT_PLUGIN_PATH environment variables to configure the search path.

  15. The application running error message gpu_data_manager_impl_private, how can I solve it?

    The current temporary solution is to add --no-container.


  16. Can the application carry the database file by itself and write data to the database during operation?

    The file system in the container is a read-only file system and does not allow data to be written to application resource files.

  17. Why does the execution of binary with suid and guid permissions fail?

    In order to ensure system security, Linglong container prohibits the execution of such permission binaries in the container.

  18. Can the input method of uab offline package format not be used under Debian and Ubuntu?

    It is recommended to install the fictx input method to experience it.