Managing virtual packages

"Virtual" packages are injected into the conda solver to allow real packages to depend on features present on the system that cannot be managed directly by conda, like system driver versions or CPU features. Virtual packages are not real packages and not displayed by conda list. Instead conda runs a small bit of code to detect the presence or absence of the system feature that corresponds to the package. The currently supported list of virtual packages includes:

  • __cuda: Maximum version of CUDA supported by the display driver.

  • __osx: OSX version if applicable.

  • __glibc: Version of glibc supported by the OS.

  • __linux: Available when running on Linux.

  • __unix: Available when running on OSX or Linux.

  • __win: Available when running on Win.

Other virtual packages will be added in future conda releases. These are denoted by a leading double-underscore in the package name.

Listing detected virtual packages

Use the terminal or an Anaconda Prompt for the following steps.

To see the list of detected virtual packages, run:

conda info

If a package is detected, you will see it listed in the virtual packages section, as shown in this example:

    active environment : base
   active env location : /Users/demo/dev/conda/devenv
           shell level : 1
      user config file : /Users/demo/.condarc
populated config files : /Users/demo/.condarc
         conda version : 4.6.3.post8+8f640d35a
   conda-build version : 3.17.8
        python version :
      virtual packages : __cuda=10.0
      base environment : /Users/demo/dev/conda/devenv (writable)
          channel URLs :
         package cache : /Users/demo/dev/conda/devenv/pkgs
      envs directories : /Users/demo/dev/conda/devenv/envs
              platform : osx-64
            user-agent : conda/4.6.3.post8+8f640d35a requests/2.21.0 CPython/3.7.2 Darwin/17.7.0 OSX/10.13.6
               UID:GID : 502:20
            netrc file : None
          offline mode : False

Overriding detected packages

For troubleshooting, it is possible to override virtual package detection using an environment variable. Supported variables include:

  • CONDA_OVERRIDE_CUDA - CUDA version number or set to "" for no CUDA detected.

  • CONDA_OVERRIDE_OSX - OSX version number or set to "" for no OSX detected.

  • CONDA_OVERRIDE_GLIBC - GLIBC version number or set to "" for no GLIBC. This only applies on Linux.