Starts evaluating an R function call in a background R process, and returns immediately.
r_bg(func, args = list(), libpath = .libPaths(),
repos = default_repos(), stdout = "|", stderr = "|",
poll_connection = TRUE, error = getOption("callr.error", "error"),
cmdargs = c("--slave", "--no-save", "--no-restore"),
system_profile = FALSE, user_profile = FALSE,
env = rcmd_safe_env(), supervise = FALSE, ...)
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. The environment of the function
is set to .GlobalEnv
before passing it to the child process.
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
r(.libPaths)
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.
The name of the file the standard output of
the child R process will be written to.
If the child process runs with the --slave
option (the default),
then the commands are not echoed and will not be shown
in the standard output. Also note that you need to call print()
explicitly to show the output of the command(s).
The name of the file the standard error of
the child R process will be written to.
In particular message()
sends output to the standard
error. If nothing was sent to the standard error, then this file
will be empty. This argument can be the same file as stdout
,
in which case they will be correctly interleaved. If this is the
string "2>&1"
, then standard error is redirected to standard output.
Whether to have a control connection to the process. This is used to transmit messages from the subprocess to the parent.
What to do if the remote process throws an error. See details below.
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.
Environment variables to set for the child process.
Whether to register the process with a supervisor. If TRUE
,
the supervisor will ensure that the process is killed when the R process
exits.
Extra arguments are passed to the processx::process constructor.
An r_process
object, which inherits from process,
so all process
methods can be called on it, and in addition it also
has a get_result()
method to collect the result.
# NOT RUN {
rx <- r_bg(function() 1 + 2)
# wait until it is done
rx$wait()
rx$is_alive()
rx$get_result()
# }
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