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<h1 align="center">R for Windows FAQ</h1>
<h2>Version for <tt>rw1020</tt></h2>
<address>B. D. Ripley</address>
<p><p><hr><p>


<h1>Table of Contents</h1>
<ul>
<li><a href="#Introduction">1 Introduction</a>
<li><a href="#Installation%20and%20Usage">2 Installation and Usage</a>
<ul>
<li><a href="#Where%20can%20I%20find%20the%20latest%20version%3f">2.1 Where can I find the latest version?</a>
<li><a href="#How%20do%20I%20install%20R%20for%20Windows%3f">2.2 How do I install R for Windows?</a>
<li><a href="#How%20do%20I%20run%20it%3f">2.3 How do I run it?</a>
<li><a href="#How%20can%20I%20keep%20workspaces%20for%20different%20projects%20in%20different%20directories%3f">2.4 How can I keep workspaces for different projects in different directories?</a>
<li><a href="#How%20do%20I%20print%20from%20R%3f">2.5 How do I print from R?</a>
<li><a href="#Can%20I%20use%20R%20BATCH%3f">2.6 Can I use <code>R BATCH</code>?</a>
<li><a href="#Can%20I%20use%20rwXxxx%20with%20ESS%20and%20emacs%3f">2.7 Can I use rwXxxx with ESS and emacs?</a>
<li><a href="#What%20are%20HOME%20and%20working%20directories%3f">2.8 What are HOME and working directories?</a>
</ul>
<li><a href="#Packages">3 Packages</a>
<ul>
<li><a href="#Can%20I%20install%20packages%20(libraries)%20in%20this%20version%3f">3.1 Can I install packages (libraries) in this version?</a>
<li><a href="#I%20don't%20have%20permission%20to%20write%20to%20the%20rwXxxx%2flibrary%20directory">3.2 I don't have permission to write to the <code>rwXxxx/library</code> directory.</a>
<li><a href="#The%20packages%20I%20installed%20do%20not%20appear%20in%20the%20HTML%20help%20system">3.3 The packages I installed do not appear in the HTML help system.</a>
<li><a href="#My%20functions%20are%20not%20found%20by%20the%20HTML%20help%20search%20system.">3.4 My functions are not found by the HTML help search system.</a>
</ul>
<li><a href="#Windows%20Features">4 Windows Features</a>
<ul>
<li><a href="#What%20should%20I%20expect%20to%20behave%20differently%20from%20the%20Unix%20version%20of%20R%3f">4.1 What should I expect to behave differently from the Unix version of R?</a>
<li><a href="#I%20hear%20about%20some%20nifty%20features.%20Please%20tell%20me%20about%20them!">4.2 I hear about some nifty features: please tell me about them!</a>
</ul>
<li><a href="#Workspaces">5 Workspaces</a>
<ul>
<li><a href="#My%20workspace%20gets%20saved%20in%20a%20strange%20place.%20how%20do%20I%20stop%20this%3f">5.1 My workspace gets saved in a strange place: how do I stop this?</a>
<li><a href="#How%20do%20I%20store%20my%20workspace%20in%20a%20different%20place%3f">5.2 How do I store my workspace in a different place?</a>
<li><a href="#Can%20I%20load%20workspaces%20saved%20under%20Unix%2fGNU-Linux%3f">5.3 Can I load workspaces saved under Unix/GNU-Linux?</a>
</ul>
<li><a href="#The%20R%20Console%20and%20Fonts">6 The R Console and Fonts</a>
<ul>
<li><a href="#I%20would%20like%20to%20be%20able%20to%20use%20Japanese%20fonts">6.1 I would like to be able to use Japanese fonts</a>
<li><a href="#I%20don't%20see%20characters%20with%20accents%20at%20the%20R%20console">6.2 I don't see characters with accents at the R console, for example in ?text.</a>
<li><a href="#The%20output%20to%20the%20console%20seems%20to%20be%20delayed">6.3 When using Rgui the output to the console seems to be delayed.</a>
<li><a href="#Long%20lines%20seem%20to%20be%20truncated.">6.4 Long lines in the console or pager are truncated.</a>
</ul>
<li><a href="#Building%20from%20Source">7 Building from Source</a>
<ul>
<li><a href="#How%20can%20I%20compile%20R%20from%20source%3f">7.1 How can I compile R from source?</a>
<li><a href="#How%20do%20I%20debug%20code%20that%20I%20have%20compiled%20and%20dyn.load-ed%3f">7.2 How do I debug code that I have compiled and dyn.load-ed?</a>
<li><a href="#How%20do%20I%20include%20C++%20code%3f">7.3 How do I include C++ code?</a>
<li><a href="#The%20output%20from%20my%20C%20code%20disappears.">7.4 The output from my C code disappears. Why?</a>
<li><a href="#The%20output%20from%20my%20Fortran%20code%20disappears.">7.5 The output from my Fortran code disappears. Why?</a>
<li><a href="#The%20console%20freezes%20when%20my%20compiled%20code%20is%20running">7.6 The console freezes when my compiled code is running.</a>
</ul>
</ul>

<a name="Top"></a>

</ul>

<p><hr>

<a name="Introduction"></a>

<h1>1 Introduction</h1>

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

<pre><a href="http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html">http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html</a>.
</pre>

<p>The information here applies only to recent versions of R for Windows,
(<code>rw1000</code> or later); the current version is often called something like
<code>rw1020</code> (although not officially).

<p><hr>

<a name="Installation%20and%20Usage"></a>

<h1>2 Installation and Usage</h1>

</ul>

<a name="Where%20can%20I%20find%20the%20latest%20version%3f"></a>

<h2>2.1 Where can I find the latest version?</h2>

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

<pre>      rwXxxxb1.zip rwXxxxb2.zip
      rwXxxxh.zip (text help) or rwXxxxch.zip (Compiled HTML help)
</pre>

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

<p>Optionally, you can download the installer, <code>rwinst.exe</code>.

<a name="How%20do%20I%20install%20R%20for%20Windows%3f"></a>

<h2>2.2 How do I install R for Windows?</h2>

<p>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).

<p>The simplest way is to run the installer (double-click on the icon for
<code>rwinst.exe</code> 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 <code>unzip</code>). All the files will unpack into a directory called
<code>rwXxxx</code>, for some <code>Xxxx</code>.

<p>Choose a working directory for R. Make a shortcut to
<code>rwXxxx\bin\Rgui.exe</code> 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.

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

<a name="How%20do%20I%20run%20it%3f"></a>

<h2>2.3 How do I run it?</h2>

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

<p>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.

<a name="How%20can%20I%20keep%20workspaces%20for%20different%20projects%20in%20different%20directories%3f"></a>

<h2>2.4 How can I keep workspaces for different projects in different directories?</h2>

<p>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.

<a name="How%20do%20I%20print%20from%20R%3f"></a>

<h2>2.5 How do I print from R?</h2>

<p>It depends what you want to print.

<ul>
<li>You can print the graphics window from its menu or by using
<code>dev.print()</code>. 
<li>You can print from the R console or pager by <code>File | Print</code>. 
<li>You can print help files from the pager or HTML browser. 
<li>If you have configured <code>RHOME\bin\helpPRINT.bat</code> and have
latex installed you can print help files by <code>help(fn_name, offline=TRUE)</code>. 
</ul>

<a name="Can%20I%20use%20R%20BATCH%3f"></a>

<h2>2.6 Can I use <code>R BATCH</code>?</h2>

<p>No, but you can set up a batch file using <code>Rterm.exe</code>. A sample batch file
might contain (as one line)

<pre>path_to_R\bin\Rterm.exe --vsize=10M --nsize=500k --no-restore --no-save &lt; %1 &gt; %1.out
</pre>

<a name="Can%20I%20use%20rwXxxx%20with%20ESS%20and%20emacs%3f"></a>

<h2>2.7 Can I use rwXxxx with ESS and emacs?</h2>

<p>Yes. The latest versions of ESS (e.g. 5.1.13) come with support for this
version of R, and there is support for interrupting the R process from
ESS (by <code>C-c C-c</code>).

<p>For help with ESS, please send email to <a href="mailto:ESS-help@stat.ethz.ch">ESS-help@stat.ethz.ch</a>,
not the R mailing lists.

<a name="What%20are%20HOME%20and%20working%20directories%3f"></a>

<h2>2.8 What are HOME and working directories?</h2>

<p>Several places in the documentation use these terms.

<p>The working directory is the directory from which <code>Rgui</code> or
<code>Rterm</code> 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 <code>getwd()</code>.

<p>The home directory is set as follows:<br>
If environment variable <code>R_USER</code> is set, its value is used.<br>
Otherwise if environment variable <code>HOME</code> is set, its value is used.<br>
Otherwise if environment variables <code>HOMEDRIVE</code> and <code>HOMEPATH</code> are set,
the value is <code>${HOMEDRIVE}${HOMEPATH}</code>.<br>
If all of these fail, the current working directory is used.

<p>You can find this from R code by <code>Sys.getenv("R_USER")</code>.

<p><hr>

<a name="Packages"></a>

<h1>3 Packages</h1>

</ul>

<a name="Can%20I%20install%20packages%20(libraries)%20in%20this%20version%3f"></a>

<h2>3.1 Can I install packages (libraries) in this version?</h2>

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

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

<a name="I%20don't%20have%20permission%20to%20write%20to%20the%20rwXxxx%2flibrary%20directory"></a>

<h2>3.2 I don't have permission to write to the <code>rwXxxx/library</code> directory.</h2>

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

<p>Suppose your packages are installed in <code>p:\mylibs</code>. Then you can EITHER

<pre>set R_LIBS to p:\mylibs
</pre>

<p>OR put in the <code>.Rprofile</code> in the working directory or your home directory

<pre>.lib.loc &lt;- c("p:/mylibs", .Library)
</pre>

<p>OR use a package by, e.g.

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

<p>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 <code>Rgui</code> / <code>Rterm</code>. 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

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

<p>and you can set variables in a file <code>.Renviron</code> in the working directory
or your home directory, for example

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

<p>The order of precedence is the command line (flags before variables)
then <code>.Renviron</code> then the inherited environment.

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

<a name="The%20packages%20I%20installed%20do%20not%20appear%20in%20the%20HTML%20help%20system"></a>

<h2>3.3 The packages I installed do not appear in the HTML help system.</h2>

<p>HTML help only works for packages installed in <code>rwXxxx\library</code>.

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

<pre>&gt; link.html.help()
</pre>

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

<pre>cd rwXxxx\src\gnuwin32\help
make indices
</pre>

<p>instead.)

<a name="My%20functions%20are%20not%20found%20by%20the%20HTML%20help%20search%20system."></a>

<h2>3.4 My functions are not found by the HTML help search system.</h2>

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

<ul>
<li>the package is installed in <code>rwXxxx\library</code>. 
<li>the package contains a <code>CONTENTS</code> file in top-level directory
(a few of the binary distributions do not). 
<li>you updated the indices as described in the answer to Q3.3 after
installing the package. 
</ul>

<p>If those all hold true, this works for us.

<p><hr>

<a name="Windows%20Features"></a>

<h1>4 Windows Features</h1>

</ul>

<a name="What%20should%20I%20expect%20to%20behave%20differently%20from%20the%20Unix%20version%20of%20R%3f"></a>

<h2>4.1 What should I expect to behave differently from the Unix version of R?</h2>

<ul>
<li>R commands can be interrupted by &lt;Esc&gt; in <code>Rgui.exe</code>
and &lt;Ctrl-break&gt; or &lt;Ctrl-C&gt; in <code>Rterm.exe</code>: &lt;Ctrl-C&gt;
is used for copying in the GUI version.

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

<li>Using <code>help.start()</code> does not automatically send help
requests to the browser: use <code>options(htmlhelp=T)</code> to turn this on.

<li>The HTML help system can only access packages installed in the standard
place.

<li>Paths to files (e.g. in <code>source()</code>) can be specified with
either "/" or "\\".

<li><code>system()</code> is slightly different: see its help page and that
of <code>shell()</code>. 
</ul>

<a name="I%20hear%20about%20some%20nifty%20features.%20Please%20tell%20me%20about%20them!"></a>

<h2>4.2 I hear about some nifty features: please tell me about them!</h2>

<p>You have read the <code>README</code>? 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 <code>png</code>, <code>jpeg</code>, <code>bmp</code>,
<code>postscript</code> or <code>metafile</code>. There are right-click menus giving
shortcuts to menu items, and optionally toolbars with buttons giving
shortcuts to frequent operations.

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

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

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

<p>There is only one graphics history shared by all the windows devices.' 
</blockquote>

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

<p><hr>

<a name="Workspaces"></a>

<h1>5 Workspaces</h1>

</ul>

<a name="My%20workspace%20gets%20saved%20in%20a%20strange%20place.%20how%20do%20I%20stop%20this%3f"></a>

<h2>5.1 My workspace gets saved in a strange place: how do I stop this?</h2>

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

<a name="How%20do%20I%20store%20my%20workspace%20in%20a%20different%20place%3f"></a>

<h2>5.2 How do I store my workspace in a different place?</h2>

<p>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.

<a name="Can%20I%20load%20workspaces%20saved%20under%20Unix%2fGNU-Linux%3f"></a>

<h2>5.3 Can I load workspaces saved under Unix/GNU-Linux?</h2>

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

<p><hr>

<a name="The%20R%20Console%20and%20Fonts"></a>

<h1>6 The R Console and Fonts</h1>

</ul>

<a name="I%20would%20like%20to%20be%20able%20to%20use%20Japanese%20fonts"></a>

<h2>6.1 I would like to be able to use Japanese fonts</h2>

<p>for example, in the console and to annotate graphs.

<p>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

<pre>par(font=, font.lab=, font.main=, font.sub=)
</pre>

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

<a name="I%20don't%20see%20characters%20with%20accents%20at%20the%20R%20console"></a>

<h2>6.2 I don't see characters with accents at the R console, for example in ?text.</h2>

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

<a name="The%20output%20to%20the%20console%20seems%20to%20be%20delayed"></a>

<h2>6.3 When using Rgui the output to the console seems to be delayed.</h2>

<p>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: &lt;Ctrl-W&gt; toggles the setting.

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

<a name="Long%20lines%20seem%20to%20be%20truncated."></a>

<h2>6.4 Long lines in the console or pager are truncated.</h2>

<p>They only <strong>seem</strong> 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 &lt;CTRL+arrow&gt; keys to scroll horizontally.

<p><hr>

<a name="Building%20from%20Source"></a>

<h1>7 Building from Source</h1>

</ul>

<a name="How%20can%20I%20compile%20R%20from%20source%3f"></a>

<h2>7.1 How can I compile R from source?</h2>

<p>Get the R sources. Suppose you want to compile R-1.2.0.

<pre>tar zxvf R-1.2.0.tgz
cd R-1.2.0
cd src\gnuwin32
</pre>

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

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

<a name="How%20do%20I%20debug%20code%20that%20I%20have%20compiled%20and%20dyn.load-ed%3f"></a>

<h2>7.2 How do I debug code that I have compiled and dyn.load-ed?</h2>

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

<pre>make clean
make DEBUG=T
</pre>

<p>and make a debug version of your package by

<pre>make DEBUG=T pkg-mypkg
</pre>

<p>Then you can debug by

<pre>gdb /path/to/rwXxxx/bin/Rgui.exe
</pre>

<p>However, note

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

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

<pre>     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&gt; library(eda)
     (gdb) break tukeyline
     (gdb) clear R_ReadConsole
     (gdb) continue
</pre>

<p>Fortran symbols need an underline appended.

</p><li>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 <code>mingw32</code>
version of <code>gdb</code>.  It does often work with the <code>cygwin</code> version.

<li>We have seen examples in debugging problems with Windows events that
the <code>cygwin gdb</code> was able to catch but which terminated the
<code>mingw32 gdb</code>. 
</ul>

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

<a name="How%20do%20I%20include%20C++%20code%3f"></a>

<h2>7.3 How do I include C++ code?</h2>

<p>You need to do two things:

<p>(a) Write a wrapper to export the symbols you want to call from R as
 <code>extern "C"</code>.

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

<pre>.../bin/Rcmd SHLIB X.cc X_main.cc
</pre>

<p>or (VC++, which requires extension <code>.cpp</code>)

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

<p>or (Borland C++, which also requires extension <code>.cpp</code>)

<pre>bcc32 -u- -WDE X.cpp X_main.cpp
</pre>

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

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

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

<a name="The%20output%20from%20my%20C%20code%20disappears."></a>

<h2>7.4 The output from my C code disappears. Why?</h2>

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

<p>Note that output from the console is delayed (see <a href="#The%20output%20to%20the%20console%20seems%20to%20be%20delayed">The output to the console seems to be delayed</a>), so that you will not normally see any
output before returning to the R prompt.

<a name="The%20output%20from%20my%20Fortran%20code%20disappears."></a>

<h2>7.5 The output from my Fortran code disappears. Why?</h2>

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

<a name="The%20console%20freezes%20when%20my%20compiled%20code%20is%20running"></a>

<h2>7.6 The console freezes when my compiled code is running.</h2>

<p>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 <code>R_ProcessEvents()</code> periodically from your compiled code. 
If you want output to be updated on the console, call
<code>R_FlushConsole()</code> and then <code>R_ProcessEvents()</code>.

<p><hr WIDTH="100%">
<address>
Last edited 2000 June 10 by Brian Ripley
<code><a href="mailto:ripley@stats.ox.ac.uk">ripley@stats.ox.ac.uk</a></code>
</address>

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