[R] How to resolve include Rcpp.h problems?

[Dirk Eddelbuettel]

On 13 December 2009 at 19:37, Romain Francois wrote:
| Hi,
| 
| The file lives in the lib directory of the installed package Rcpp.
| 
| Rscript -e "cat(system.file( 'lib', 'Rcpp.h', package = 'Rcpp' ))"

Yes, and we typically use similar tricks to build with Rcpp -- suppose your
file is called myfile.cpp then you can use (if you have littler)

     PKG_CPPFLAGS=`r -e'Rcpp:::CxxFlags()'` \
         PKG_LIBS=`r -e'Rcpp:::LdFlags()'` \
	 R CMD SHLIB myfile.cpp

and R CMD SHLIB will know where to find Rcpp.h and the other headers as well
as libRcpp.so (or .a). 

If you don't have littler, you can use the same with Rscript as well

     PKG_CPPFLAGS=`Rscript -e 'Rcpp:::CxxFlags()'` \
         PKG_LIBS=`Rscript -e 'Rcpp:::LdFlags()'` \
	 R CMD SHLIB myfile.cpp

and that should work portably.  Likewise, you can set
PKG_CPPFLAGS and PKG_LIBS in src/Makevars if you build a package.

I am right working on integrating the cfunction() from the rather useful
inline package into Rcpp; this may also appear appear in the inline package
itself if its maintainer accepts my patch and makes a new release.  With
version in SVN you can now say

-----------------------------------------------------------------------------
suppressMessages(library(Rcpp))

foo <- '
  SEXP  rl = R_NilValue;        // Use this when there is nothing to be returned.
  char* exceptionMesg = NULL;   // msg var in case of error

  try {
    RcppVector<int> vec(v);     // vec parameter viewed as vector of ints.
    int n = vec.size(), i = 0;
    if (n != 10000) throw std::length_error("Wrong vector size");
    for (int a = 0; a < 9; a++)
      for (int b = 0; b < 9; b++)
        for (int c = 0; c < 9; c++)
          for (int d = 0; d < 9; d++)
            vec(i++) = a*b - c*d;

    RcppResultSet rs;           // Build result set to be returned as a list to R.
    rs.add("vec", vec);         // vec as named element with name "vec"
    rl = rs.getReturnList();    // Get the list to be returned to R.
  } catch(std::exception& ex) {
    exceptionMesg = copyMessageToR(ex.what());
  } catch(...) {
    exceptionMesg = copyMessageToR("unknown reason");
  }

  if (exceptionMesg != NULL) Rf_error(exceptionMesg);

  return rl;
'

funx <- cfunction(signature(v="numeric"), foo, Rcpp=TRUE)

dd.inline.rcpp <- function() {
    x <- integer(10000)
    res <- funx(v=x)[[1]]
    tabulate(res)
}

print(mean(replicate(100,system.time(dd.inline.rcpp())["elapsed"]),trim=0.05))
-----------------------------------------------------------------------------

which means everything works from within R which is rather convenient. I am
currently extending this for arguments for additional header files and
libraries.

| The maintainer of Rcpp (cc'ed, just in case) will tell you more tricks. 
| Note that Rcpp has its own mailing list. 
| https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel 
| where questions like this might be more appropriate.

Hehe. So far that mailing has only Romain and myself rambling along.

Dirk

| Romain
| 
| On 12/13/2009 09:56 AM, Amine Jallouli wrote:
| >
| > Hi,
| > I am Linux Ubuntu 9.04 user. I'm using R-2.6.
| >
| > Actually, I am developing R package for reading/writing 3D images. I needed
| > to use  the R package Rcpp in order to make profit of available C/C++ codes.
| > My problem is that my C code is not able to include the Rcpp.h
| >
| > In fact, when I run this command R CMD build rply, I got the following error
| > message in the file /home/amine/R/r-eclipse/rply.Rcheck/00install.out:
| > * Installing *source* package 'rply' ...
| > ** libs
| > gcc -std=gnu99 -I/usr/share/R/include      -fpic  -g -O2 -c Call_interface.c
| > -o Call_interface.o
| > gcc -std=gnu99 -I/usr/share/R/include      -fpic  -g -O2 -c C_interface.c -o
| > C_interface.o
| > gcc -std=gnu99 -I/usr/share/R/include      -fpic  -g -O2 -c fifrt.c -o
| > fifrt.o
| > g++ -I/usr/share/R/include      -fpic  -g -O2 -c RCPP_test.cpp -o
| > RCPP_test.o
| > RCPP_test.cpp:1:18: erreur: Rcpp.h : No such file or directory
| > RCPP_test.cpp: In function ‘SEXPREC* readRIntVec(SEXPREC*)’:
| > RCPP_test.cpp:14: erreur: ‘RcppVector’ was not declared in this scope
| > RCPP_test.cpp:14: erreur: expected primary-expression before ‘int’
| > RCPP_test.cpp:14: erreur: expected `;' before ‘int’
| > make: *** [RCPP_test.o] Erreur 1
| > ERROR: compilation failed for package 'rply'
| > ** Removing '/home/amine/R/r-eclipse/rply.Rcheck/rply'
| >
| > It is evident that I will this error since the file Rcpp.h is not in this
| > directory /usr/share/R/include .
| >
| > I tried to solve this include problem by copying the Rcpp.h to
| > /usr/share/R/include. But, it was not successful and I the following error
| > message.
| >
| > Error in dyn.load(file, DLLpath = DLLpath, ...) :
| >    Unable to load shared library
| > '/home/amine/R/r-eclipse/rply.Rcheck/rply/libs/rply.so':
| >    /home/amine/R/r-eclipse/rply.Rcheck/rply/libs/rply.so: undefined symbol:
| > _ZN10RcppVectorIiEC1EP7SEXPREC
| > Error in library(rply) : .First.lib has failed for 'rply'
| > Execution stopped
| >
| > It looks like this package has a loading problem: see the messages for
| > details.
| >
| >
| > Resulting this last error seems to be also logical. In fact, I think the
| > file libRcpp.so is need for the compilation of my code.
| >
| > Please notice that the package Rcpp is installed in the following directory:
| > /usr/lib/R/site-library/Rcpp
| >
| > Thank you for giving an idea for solving this problem.
| 
| 
| -- 
| Romain Francois
| Professional R Enthusiast
| +33(0) 6 28 91 30 30
| http://romainfrancois.blog.free.fr
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| 

-- 
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