# Environment variables

You can modify the run-time behaviour by setting environment variables:

G_MESSAGES_DEBUG

  Controls the output of the library. By default nothing is printed on stdout. Set this to all to see debug output.

UFO_PLUGIN_PATH

  Colon-separated list of paths in which plugin manager looks for additional task modules. The plugins are load with descending priority.

UFO_KERNEL_PATH

  Colon-separated list of search paths for OpenCL kernel files.

UFO_DEVICES

  Controls which OpenCL devices should be used. It works similar to the CUDA_VISIBLE_DEVICES environment variables, i.e. set it to 0,2 to choose the first and third device that’s available.

UFO_DEVICE_TYPE

  Controls which OpenCL device types should be considered for execution. The variable is a comma-separated list with strings being cpu, gpu and acc, i.e. to use both CPU and GPUs set UFO_DEVICE_TYPE=”cpu,gpu”.