[Rd] FW: [Rcpp-devel] Question on 5.6 Interfacing C++ code

Thu Apr 21 16:52:35 CEST 2011

Thanks,
That's great, but I don't know how to determine what foo is. How do I
declare the name of the package?

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 I¹m 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 it¹s 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
>> 
> 