R for Windows FAQ

Frequently Asked Questions on R for Windows

Version for

Brian Ripley

Introduction
************

This FAQ is for the Windows port of R: it describes features specific to that version. The main R FAQ can be found at

     http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html.

The information here applies only to recent versions of R for Windows, (rw1000 or later); the current version is often called something like (although not officially).

Installation and Usage
**********************

Where can I find the latest version?
====================================

Go to any CRAN site (see http://cran.r-project.org/mirrors.html for a list), navigate to the bin/windows/windows-NT/base directory and collect the files you need. You will need at least the files

           rwXxxxb1.zip rwXxxxb2.zip
           rwXxxxh.zip (text help) or rwXxxxch.zip (Compiled HTML help)

and you may want rwXxxxwh.zip (the Windows help files) or rwXxxxw.zip (the HTML format help files), rwXxxxl.zip (the LaTeX format help files, used for offline printing), or rwXxxxd?.zip (the draft manuals, in PDF).

Optionally, you can download the installer, rwinst.exe.

How do I install R for Windows?
===============================

First, you need Windows 95 or 98 or NT4 or 2000: Windows 3.11+win32s will not work. Your file system must allow long file names (as is likely except perhaps for some network-mounted systems).

The simplest way is to run the installer (double-click on the icon for rwinst.exe and navigate its wizard-like pages).  Alternatively, choose a location and unzip the zip files (with a tool that preserves long file names and the directory structure: we recommend the INFO-ZIP project's unzip). All the files will unpack into a directory called rwXxxx, for some Xxxx.

Choose a working directory for R. Make a shortcut to rwXxxx\bin\Rgui.exe on your desktop or somewhere on the Start menu file tree. Right-click the shortcut, select Properties... and change the `Start in' field to your working directory.

You may also want to add command-line arguments at the end of the Target field, for example --vsize=10M --nsize=400k. You can also set environment variables at the end of the Target field, for example R_LIBS=e:/R/library.

How do I run it?
================

Just double-click on the shortcut you prepared at installation.

If you want to set up another project, make a new shortcut or use the existing one, and change the `Start in' field of the Properties.

How can I keep workspaces for different projects in different directories?
==========================================================================

Create a separate shortcut for each project: see Q2.3. All the paths to files used by R are relative to the starting directory, so setting the `Start in' field automatically helps separate projects.

How do I print from R?
======================

It depends what you want to print.

  * You can print the graphics window from its menu or by using dev.print().

  * You can print from the R console or pager by File | Print.

  * You can print help files from the pager or HTML browser.

  * If you have configured RHOME\bin\helpPRINT.bat and have latex installed you can print help files by help(fn_name, offline=TRUE).

Can I use R BATCH?
==================

Yes, if you Perl installed.  The Windows analogue is Rcmd BATCH: use Rcmd BATCH --help for full details.

Otherwise you can set up a batch file using Rterm.exe. A sample batch file might contain (as one line)

     path_to_R\bin\Rterm.exe --no-restore --no-save < %1 > %1.out

Can I use rwXxxx with ESS and emacs?
====================================

Yes. The latest versions of ESS (e.g. 5.1.16) come with support for this version of R, and there is support for interrupting the R process from ESS (by C-c C-c).

For help with ESS, please send email to ESS-help@stat.ethz.ch, not the R mailing lists.

What are HOME and working directories?
======================================

Several places in the documentation use these terms.

The working directory is the directory from which Rgui or Rterm was launched, unless a shortcut was used when it is given by the `Start in' field of the shortcut's properties. You can find this from R code by the call getwd().

The home directory is set as follows:

If environment variable R_USER is set, its value is used.

Otherwise if environment variable HOME is set, its value is used.

Otherwise if environment variables HOMEDRIVE and HOMEPATH are set, the value is ${HOMEDRIVE}${HOMEPATH}.

If all of these fail, the current working directory is used.

You can find this from R code by Sys.getenv("R_USER").

Packages
********

Can I install packages (libraries) in this version?
===================================================

Yes, of course. The easy way is to see if a pre-compiled binary version of the package is available: look on CRAN at bin/windows/windows-NT/contrib. If there is, download the zip file and unpack it in the rwXxxx\library directory, using unzip or similar, or using the installer rwinst.exe. Perhaps even easier is to use the R function install.packages(): check out its help page.

If there is not a binary version or that is not up-to-date or you prefer compiling from source, get rwXxxxsp.zip from the distribution (see Q1.1) and unpack it in rwXxxx. Then cd src\gnuwin32 and read README.packages. You will need to collect and install several tools to use this. Once you have done so, installation is easy: just run make pkg-pkgname. To check the package (run all the examples on its help pages) use make pkgcheck-pkgname.

I don't have permission to write to the rwXxxx/library directory.
=================================================================

You can install packages anywhere and use the environment variable R_LIBS to point to the library location(s). You can also set the R variable .lib.loc in your .Rprofile or when running R.

Suppose your packages are installed in p:\mylibs. Then you can EITHER

     set R_LIBS to p:\mylibs

OR put in the .Rprofile in the working directory or your home directory

     .lib.loc <- c("p:/mylibs", .Library)

OR use a package by, e.g.

     library(MASS, lib.loc="p:/mylibs")

How you set an environment variable is system specific: in Windows 9x you can set them in autoexec.bat or in an MS-DOS window from which you launch Rgui / Rterm. Under Windows NT/2000 you can use the control panel or the properties of `My Computer'. You can also set them on the command line, for example in the shortcut you could have

     path_to_R\bin\Rgui.exe --vsize=10M R_LIBS=e:/R/library

and you can set variables in a file .Renviron in the working directory or your home directory, for example

     R_LIBS=e:/R/library
     R_VSIZE=10M
     R_NSIZE=400k

The order of precedence is the command line (flags before variables) then .Renviron then the inherited environment.

You can also build packages from anywhere to anywhere, but may be simpler to install a private copy of R to do the building.

The packages I installed do not appear in the HTML help system.
===============================================================

HTML help only works for packages installed in rwXxxx\library.

To update the HTML help files after you have installed a binary package, run at the R prompt.

     > link.html.help()

(Using install.packages() does this for you.  The source-code installation also does this automatically, and if you have that installed you can use (preferably)

     cd rwXxxx\src\gnuwin32\help
     make indices

instead.)

My functions are not found by the HTML help search system.
==========================================================

The following conditions need to hold for functions in a package you installed.

  * the package is installed in rwXxxx\library.

  * the package contains a CONTENTS file in top-level directory (a few of the binary distributions do not).

  * you updated the indices as described in the answer to Q3.3 after installing the package.

If those all hold true, this works for us.

Windows Features
****************

What should I expect to behave differently from the Unix version of R?
======================================================================

  * R commands can be interrupted by Esc in Rgui.exe and Ctrl-break or Ctrl-C in Rterm.exe: Ctrl-C is used for copying in the GUI version.

  * Command-line editing is always available, but is simpler than the readline-based editing on Unix. For Rgui.exe, the menu item `Help | Console' will give details.

  * Using help.start() does not automatically send help requests to the browser: use options(htmlhelp=T) to turn this on.

  * The HTML help system can only access packages installed in the standard place.

  * Paths to files (e.g. in source()) can be specified with either "/" or "\\".

  * system() is slightly different: see its help page and that of shell().

I hear about some nifty features: please tell me about them!
============================================================

You have read the README? There are file menus on the R console, pager and graphics windows. You can source and save from those menus, and copy the graphics to png, jpeg, bmp, postscript or metafile. There are right-click menus giving shortcuts to menu items, and optionally toolbars with buttons giving shortcuts to frequent operations.

If you resize the R console the options(width=) is automatically set to the console width (unless disabled in the configuration file).

The graphics has a history mechanism. As the README says:

     `The History menu allows the recording of plots. When plots have been recorded they can be reviewed by PgUp and PgDn, saved and replaced.  Recording can be turned on automatically (the Recording item on the list) or individual plots can be added (Add or the INS key). The whole plot history can be saved to or retrieved from an R variable in the global environment.

     There is only one graphics history shared by all the windows devices.'

The R console and graphics windows have configuration files stored in the RHOME\etc directory called Rconsole and Rdevga; you can keep personal copies in your HOME directory. They contain comments which should suffice for you to edit them to your preferences. For more details see ?Rconsole.  From rw1010 there is a Preferences editor invoked from the Edit menu which can be used to edit the file Rconsole.

Workspaces
**********

My workspace gets saved in a strange place: how do I stop this?
===============================================================

Have you changed the working directory?: see Q5.2.

How do I store my workspace in a different place?
=================================================

Use the `File | Change Dir' menu item to select a new working directory: this defaults to the last directory you loaded a file from. The workspace is saved in the working directory. You can also save a snapshot of the workspace from the `Save Workspace' menu item.

Can I load workspaces saved under Unix/GNU-Linux?
=================================================

Yes. The converse (saving on Windows, loading on Unix) also works.

The R Console and Fonts
***********************

I would like to be able to use Japanese fonts
=============================================

for example, in the console and to annotate graphs.

We believe this is possible by setting suitable fonts in the Rconsole and Rdevga configuration files (see Q4.2). You can specify additional fonts in Rdevga, and use them by

     par(font=, font.lab=, font.main=, font.sub=)

Nineteen fonts are specified (as 1 to 19) by default: you can add to these (up to 13 more) or replace them.

I don't see characters with accents at the R console, for example in ?text.
===========================================================================

You need to specify a font in Rconsole (see Q4.2) that supports latin1 encoding. The default, Courier New, does on our systems, as does FixedSys.  This may be a problem in other locales, especially for non-Western European languages.

When using Rgui the output to the console seems to be delayed.
==============================================================

This is deliberate: the console output is buffered and re-written in chunks to be less distracting. You can turn buffering off or on from the Misc menu or the right-click menu: Ctrl-W toggles the setting.

If you are sourcing R code or writing from a function, there is another option. A call to the R function flush.console() will write out the buffer and so update the console.

Long lines in the console or pager are truncated.
=================================================

They only seem to be truncated: that $ at the end indicates you can scroll the window to see the rest of the message. Use the horizontal scrollbar or the CTRL+arrow keys to scroll horizontally.

Building from Source
********************

How can I compile R from source?
================================

Get the R sources. Suppose you want to compile R-.

     tar zxvf R-.tgz
     cd R-
     cd src\gnuwin32

Now read the INSTALL file and set up all the tools needed. Then you can just use make, sit back and wait. (A complete build takes about 15 minutes on a 300MHz PII with a fast local disc.)

You may need to compile under a case-honouring file system: we found that a samba-mounted file system (which maps all file names to lower case) did not work.

How do I debug code that I have compiled and dyn.load-ed?
=========================================================

First, build a version of the R system with debugging information by

     make clean
     make DEBUG=T

and make a debug version of your package by

     make DEBUG=T pkg-mypkg

Then you can debug by

     gdb /path/to/rwXxxx/bin/Rgui.exe

However, note

  * gdb will only be able to find the source code if we run in the location where the source was compiled (rwXxxx/src/gnuwin32 for the main system, rwXxxx/src/library/mypkg/src for a package), unless told otherwise by the directory command. It is most convenient to set a list of code locations via directory commands in the file .gdbinit in the directory from which gdb is run.

  * It is only possible to set breakpoints in a DLL after the DLL has been loaded. So a way to examine the function tukeyline in package eda might be

               gdb ../../../../bin/Rgui.exe
               (gdb) break WinMain
               (gdb) run
               [ stops with R.dll loaded ]
               (gdb) break R_ReadConsole
               (gdb) continue
               [ stops with console running ]
               (gdb) continue
               Rconsole> library(eda)
               (gdb) break tukeyline
               (gdb) clear R_ReadConsole
               (gdb) continue

     Fortran symbols need an underline appended.

  * Windows has little support for signals, so the usual idea of running a program under a debugger and sending it a signal to interrupt it and drop control back to the debugger does not work with mingw32 version of gdb.  It does often work with the cygwin version.

  * We have seen examples in debugging problems with Windows events that the cygwin gdb was able to catch but which terminated the mingw32 gdb.

If you have an X server available on the PC, there is a version of DDD available that runs under the cygwin emulation layer (follow the links at http://sources.redhat.com/cygwin) and provides a graphical user interface to gdb.  Another (Windows-native) GUI for gdb is Insight, part of the latest cygwin version of gdb

How do I include C++ code?
==========================

You need to do two things:

(a) Write a wrapper to export the symbols you want to call from R as extern "C".

(b) Include the C++ libraries in the link to make the DLL. Suppose X.cc contains your C++ code, and X_main.cc is the wrapper, as in the example in `Writing R Extensions'. Then build the DLL by (gcc-2.95)

     .../bin/Rcmd SHLIB X.cc X_main.cc

or (VC++, which requires extension .cpp)

     cl /MT /c X.cpp X_main.cpp
     link /dll /out:X.dll /export:X_main X.obj X_main.obj

or (Borland C++, which also requires extension .cpp)

     bcc32 -u- -WDE X.cpp X_main.cpp

and call the entry point(s) in X_R, such as X_main. Construction of static variables will occur when the DLL is loaded, and destruction when the DLL is unloaded, usually when R terminates.

Note that you will not see the messages from this example in the GUI console: see the next section.

This example is in package cxx_0.0-0.tar.gz in the src/contrib/Devel section on CRAN, and that can be compiled as package in the usual way on Windows.

The output from my C code disappears. Why?
==========================================

The Rgui.exe console is a Windows application: writing to stdout or stderr will not produce output in the console. (This will work with Rterm.exe.)  Use Rprintf or REprintf instead. These are declared in header file R_ext/PrtUtil.h.

Note that output from the console is delayed (see The output to the console seems to be delayed), so that you will not normally see any output before returning to the R prompt.

The output from my Fortran code disappears. Why?
================================================

Writing to Fortran output writes to a file, not the Rgui console. Use one of the subroutines dblepr, intpr or realpr documented in the `Writing R Extensions' manual.

The console freezes when my compiled code is running.
=====================================================

The console, pagers and graphics window all run in the same thread as the R engine.  To allow the console etc to respond to Windows events, call R_ProcessEvents() periodically from your compiled code. If you want output to be updated on the console, call R_FlushConsole() and then R_ProcessEvents().

Last edited 2000 June 10 by Brian Ripley <ripley@stats.ox.ac.uk>