From simon.urbanek at r-project.org  Thu Apr 21 16:57:19 2011
From: simon.urbanek at r-project.org (Simon Urbanek)
Date: Thu, 21 Apr 2011 10:57:19 -0400
Subject: [Rd] FW: [Rcpp-devel] Question on 5.6 Interfacing C++ code
In-Reply-To: <C9D5BCF3.3DC6%sean.mcguffee@gmail.com>
References: <C9D5BCF3.3DC6%sean.mcguffee@gmail.com>
Message-ID: <BC806D73-DE3B-424B-8F57-0A2803286439@r-project.org>


On Apr 21, 2011, at 10:52 AM, Sean Robert McGuffee wrote:

> Thanks,
> That's great, but I don't know how to determine what foo is.

It's the name of your package.


> How do I declare the name of the package?
> 

in DESCRIPTION:
Package: name

and the directory of your package has to have the same name - please do read
http://r.research.att.com/man/R-exts.html#Creating-R-packages

Cheers,
Simon


> 
> On 4/21/11 7:16 AM, "Duncan Murdoch" <murdoch.duncan at gmail.com> wrote:
> 
>> On 11-04-20 11:33 AM, Sean Robert McGuffee wrote:
>>> Hi, apparently I sent my question about using R and C++ to the wrong list,
>>> ironically seeing as that list was called Rcpp. Anyway, I was directed to
>>> post my question here. To summarize my current question, I have found two
>>> commands that I want to be able to put into a package. The commands are 'R
>>> CMD SHLIB X.cc X_main.cc' and
>>> 'dyn.load(paste("X",.Platform$dynlib.ext,sep="")),' which I would like to
>>> run when my package is installed and maybe have the second command run again
>>> when my package is to be used. I've been trying to figure out the
>>> documentation and learn through examples, but I'm just not getting it and
>>> have been trying for weeks.
>>> Does anyone on this site have any suggestions for me?
>> 
>> Assuming those lines work on their own, just do the following:
>> 
>> 1.  Put those *.cc files into the src directory of your package.  (You
>> may need to create it.)
>> 
>> 2.  Put useDynLib(foo) into the NAMESPACE file of your foo package.
>> 
>> 3.  Call those functions using .C("X", args, PACKAGE="foo").
>> 
>> That's it.
>> 
>> Duncan Murdoch
>> 
>>> Thanks, Sean
>>> 
>>> |On 20 April 2011 at 10:20, Sean Robert McGuffee wrote:
>>> |
>>> |
>>> | Hi, thanks!
>>> |
>>> |>On 4/20/11 10:03 AM, "Steve Lianoglou"<mailinglist.honeypot at gmail.com>
>>> wrote:
>>> |>  Hi,
>>> |>
>>> |>  On Wed, Apr 20, 2011 at 9:49 AM, Sean Robert McGuffee
>>> |>  <sean.mcguffee at gmail.com>  wrote:
>>> |>>  Hi, I have a quick couple of questions about some of the documentation
>>> on
>>> |>>  the web page:
>>> |>>
>>> http://cran.r-project.org/doc/manuals/R-exts.html#Linking-GUIs-and-other-fro
>>> n
>>> |>>  t_002dends-to-R
>>> |>>  under the heading:
>>> |>>  5.6 Interfacing C++ code
>>> |>>
>>> |>>  Question 1:
>>> |>>  If I?m at a terminal, I can type the instructions they suggest:
>>> |>>  R CMD SHLIB X.cc X_main.cc
>>> |>>  If I wanted a package to do this, how would I tell the package to do
>>> that
>>> |>>  same thing?
>>> |>
>>> |>  Just to make sure we're all on the same page, you want an R package to
>>> |>  compile some source code into a shared library/dll from inside R?
>>> |>
>>> |>  Not sure if there's a "baked in" way for that to happen, but maybe you
>>> |>  can invoke `R CMD WHATEVER` from inside R using the `system` function:
>>> |>
>>> |>  R>  ?system
>>> |>
>>> |
>>> | ok, so where in the package would I put the system call in the package to
>>> | have it run when installing the package?
>>> 
>>>> You don't. As I said, 'R CMD INSTALL' et all do that.
>>>> Download an existing package with source, install it.  Study its sources,
>>>> study the 'Writing R Extensions' manual.  Ask on r-devel.
>>>> Basic R questions are off-topic here.
>>> 
>>> |>>  Would I use the same command and just include it in a file somewhere in
>>> the
>>> |>>  package?
>>> |>>  If so, which file?
>>> |>
>>> |>  Hmm ... I'm curious what you're trying to do, exactly?
>>> |
>>> | I'm trying to figure out how take commands such as " R CMD SHLIB X.cc
>>> | X_main.cc" followed by "dyn.load(paste("X", .Platform$dynlib.ext, sep =
>>> | ""))," which are commands I can get to work for myself as a human
>>> | interactively, and put the commands into a package to be automatically run
>>> | when installing the package. I mean, it's great if I can compile a c++
>>> file
>>> | and then use it inside R, but I'm only doing that so I can let other
>>> people
>>> | do that via a package. As much as I read this documentation, I keep
>>> missing
>>> 
>>>> Again, I like working from an existing, working package. As I said, there
>>>> are
>>>> almost 1000 to pick from.
>>>> Please direct follow-ups that have no bearing on Rcpp to r-devel.
>>>> Dirk
>>> 
>>> I've tried to figure this out for weeks by looking at other packages and
>>> reading the confusing and nonintegrated documentation, but it hasn't taught
>>> me how to put the two commands into a package so that they are run when the
>>> package is installed. I'm simply trying to find out where in my package I
>>> should put the commands 'R CMD SHLIB X.cc X_main.cc' and
>>> 'dyn.load(paste("X",.Platform$dynlib.ext,sep="")),'
>>> in order to have them run when my package is installed.
>>> 
>>> 
>>> | the connections between the different sections. This is a section I am
>>> | loving because it works very well. Thus, I want to figure out how to take
>>> | the baby steps I'm doing and combine them into a package. Specifically, I
>>> | want to take these two commands and insert them into a package so that
>>> these
>>> | commands will compile my code and make a dynamic ".so" file where R can
>>> | access its functions when others install my package.
>>> |
>>> |>
>>> |>>  Question 2:
>>> |>>  dyn.load(paste("X", .Platform$dynlib.ext, sep = ""))
>>> |>>
>>> |>>  Where does .Platform$dynlib.ext come from?
>>> |>>  What does it mean?
>>> |>>  What do it?s components .Platform and $dynlib and .ext mean?
>>> |>
>>> |>  .Platform is lust a normal list -- it is defined internally (I guess).
>>> |>  You can access "named" elements of a list with `$`.
>>> |>
>>> |>  .Platform$dynlyb (or .Platform[['dynlib']]) tells you the extension
>>> |>  your particular system uses for shared libraries:
>>> |>
>>> |>  R>  .Platform
>>> |>  $OS.type
>>> |>  [1] "unix"
>>> |>
>>> |>  $file.sep
>>> |>  [1] "/"
>>> |>
>>> |>  $dynlib.ext
>>> |>  [1] ".so"
>>> |>
>>> |>  $GUI
>>> |>  [1] "X11"
>>> |>
>>> |>  $endian
>>> |>  [1] "little"
>>> |>
>>> |>  $pkgType
>>> |>  [1] "mac.binary.leopard"
>>> |>
>>> |>  $path.sep
>>> |>  [1] ":"
>>> |>
>>> |>  $r_arch
>>> |>  [1] "x86_64"
>>> |>
>>> |>  See ?.Platform for more help.
>>> |
>>> | Ah, thanks, that clarifies exactly what .Platform$dynlib.ext is, it's
>>> ".so"
>>> | on my system.
>>> |
>>> | This, the dyn.load(paste("X", .Platform$dynlib.ext, sep = "")) is
>>> equivalent
>>> | to the command dyn.load("X.so) which now makes sense in that context!
>>> |
>>> |
>>> | _______________________________________________
>>> | Rcpp-devel mailing list
>>> | Rcpp-devel at lists.r-forge.r-project.org
>>> | https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel
>>> 
>> 
> 
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[Rd] FW: [Rcpp-devel] Question on 5.6 Interfacing C++ code
Simon Urbanek