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Differences to r():

  • No extra repositories are set up.

  • The --no-save, --no-restore command line arguments are not used. (But --slave still is.)

  • The system profile and the user profile are loaded.

  • No extra environment variables are set up.


  args = list(),
  libpath = .libPaths(),
  repos = getOption("repos"),
  cmdargs = "--slave",
  system_profile = TRUE,
  user_profile = TRUE,
  env = character(),



Function object to call in the new R process. The function should be self-contained and only refer to other functions and use variables explicitly from other packages using the :: notation. By default the environment of the function is set to .GlobalEnv before passing it to the child process. (See the package option if you want to keep the environment.) Because of this, it is good practice to create an anonymous function and pass that to callr, instead of passing a function object from a (base or other) package. In particular


does not work, because .libPaths is defined in a special environment, but

r(function() .libPaths())

works just fine.


Arguments to pass to the function. Must be a list.


The library path.


The repos option. If NULL, then no repos option is set. This options is only used if user_profile or system_profile is set FALSE, as it is set using the system or the user profile.


Command line arguments to pass to the R process. Note that c("-f", rscript) is appended to this, rscript is the name of the script file to run. This contains a call to the supplied function and some error handling code.


Whether to use the system profile file.


Whether to use the user's profile file. If this is "project", then only the profile from the working directory is used, but the R_PROFILE_USER environment variable and the user level profile are not. See also "Security considerations" below.


Environment variables to set for the child process.


Additional arguments are passed to r().

Security considerations

callr makes a copy of the user's .Renviron file and potentially of the local or user .Rprofile, in the session temporary directory. Avoid storing sensitive information such as passwords, in your environment file or your profile, otherwise this information will get scattered in various files, at least temporarily, until the subprocess finishes. You can use the keyring package to avoid passwords in plain files.

See also

Other callr functions: r_vanilla(), r()