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Device-specific plugin libraries for BUTool can be loaded in three different ways: from the command line, from setting an environment variable, and from a config file (located at /etc/BUTool). The functionality for loading plugins from the environment variable and the config file is implemented in the main BUTool.cxx file.

After loading a plugin library, the device class corresponding to that library will be registered with BUTool, and can be added manually with the add_device command.


In order to load plugins from the command line, you need to launch BUTool with the following arguments:

BUTool.exe --cmd add_lib /path/to/

The --cmd flag tells BUTool to run the add_lib command, which loads the specified plugin library and registers the associated device with BUTool.

Environment variable

Plugin libraries can be automatically loaded to the installed BUTool executable by setting the BUTOOL_AUTOLOAD_LIBRARY_LIST environment variable with the absolute paths to every desired plugin library.

For instance, on Apollo SM02, BUTOOL_AUTOLOAD_LIBRARY_LIST contains the default installation paths of all device libraries:

[cms@apollo02 ~]$ echo $BUTOOL_AUTOLOAD_LIBRARY_LIST

Then, upon running BUTool the plugins are automatically loaded and the devices registered:

[cms@apollo02 ~]$ BUTool.exe
Registered device: GENERICIPBUS
Registered device: APOLLOSM
Registered device: IPMISOL

Config file

Finally, plugins can be automatically loaded to BUTool through the use of a config file, which should be located at /etc/BUTool. The config file can contain the paths of plugin libraries as well as the name and arguments of the default device to be loaded (see 'Adding a Device').

To specify a plugin library to load on BUTool startup, add the line


Multiple plugins can be loaded by specifying multiple lib arguments.

On Apollo SM02, for example, the config file contains: