[Rcpp-devel] Rcpp shared libraries (?)

[Serguei Sokol]

Rcpp or plain C++ or even C ;) , you still have to declare used functions.
In Rcpp package, the most natural way to do it, is to put such 
declarations in a file $pkg/inst/include/<pkg_name>.h. In your case, it 
will be inst/include/ade4.h

In this file you put:

#include <RcppArmadillo.h>
int matcentrageCpp (arma::mat& A, const arma::vec& poili, const int typ);

and all other functions of yours you plan to use in a cross-file way.
Then, in a file where you want to use such functions (e.g. in 
testertracenuCpp.cpp), you add

#include <ade4.h>

Finally, you add the following line in your src/Makevars:

PKG_CPPFLAGS = -I../inst/include

After all this, I've got a compilation without error.
I can make a PR if you wish.

Best,
Serguei.

Le 23/06/2022 à 16:10, Jean Thioulouse a écrit :
> 
> 
>> Le 23 juin 2022 à 16:04, Serguei Sokol <serguei.sokol at gmail.com> a écrit :
>>
>> Le 23/06/2022 à 15:47, Jean Thioulouse a écrit :
>>> Thank you Serguei, I tried this, but I still get the "undeclared identifier" error for these internal functions during package compilation:
>>> clang++ -arch arm64 -std=gnu++14 -I"/Library/Frameworks/R.framework/Resources/include" -DNDEBUG  -I'/Library/Frameworks/R.framework/Versions/4.2-arm64/Resources/library/Rcpp/include' -I'/Library/Frameworks/R.framework/Versions/4.2-arm64/Resources/library/RcppArmadillo/include' -I/opt/R/arm64/include   -fPIC  -falign-functions=64 -Wall -g -O2  -c testertracenuCpp.cpp -o testertracenuCpp.o
>>> testertracenuCpp.cpp:112:9: error: use of undeclared identifier 'matcentrageCpp'
>>>      i = matcentrageCpp (ti1p, pl, typ1);
>> I cannot find 'matcentrageCpp' in https://github.com/sdray/ade4/tree/ade4-Rcpp/. Do you have a current state example somewhere?
> 
> Yes, I just pushed it in the ade4-Rcpp branch.
> 
>>
>> Serguei.
>>
>>>          ^
>>> Jean
>>>> Le 23 juin 2022 à 15:17, Serguei Sokol <serguei.sokol at gmail.com> a écrit :
>>>>
>>>> Le 23/06/2022 à 15:02, THIOULOUSE JEAN a écrit :
>>>>> Hi
>>>>> Sorry to bother you again with my C/C++ problems in the ade4 package (available on CRAN & GitHub).
>>>>> Thanks to your help, I have succeeded in converting several of the C functions to C++ using Rcpp. Now the package compiles without problem and all my C++ functions run fine in the dedicated GitHub branch of the package (ade4-Rcpp).
>>>>> The new problem I am facing now is that in ade4, I use a library of about 30 utilities functions collected in one file named adesub.c, with adesub.h headers file. From what I understand, during package compilation these functions are added to the ade4 shared library and they can be called by my other C functions without being declared in the init.c or NAMESPACE files, as they do not need to be known by R.
>>>>> I would like to know if it is possible to do the same thing in C++ with Rcpp.
>>>> If I understand correctly you goal, just don't put "// [[Rcpp::export]]" before your "internal" functions. They will be available to all C and C++ functions in src/ but not seen in R. You don't need extra "R CMD SHLIB" either.
>>>>
>>>> Best,
>>>> Serguei.
>>>>
>>>> I have found reading the documentation (Dirk's book and Rcpp vignettes) that I could use R CMD SHLIB to build a shared library and then dyn.load it in R. I have created a file named ade4lib.cpp containing the utilities functions in the src directory, and I can make the shared library (ade4lib.so) with RCMD SHLIB. But this does not solve my problem because, as I understand it, this makes the utilities library functions available to R (which is useless since they are not interfaced correctly to R but to C++), and not to the other C++ functions (which is what i need to do).
>>>>> Can anybody see where I am mistaken, and point me to the right direction to accomplish this ?
>>>>> Thank you,
>>>>> Jean
>>>>> —-
>>>>> Jean THIOULOUSE - https://lbbe-web.univ-lyon1.fr/en/annuaires-des-membres/thioulouse-jean
>>>>> https://orcid.org/0000-0001-7664-0598 (ORCID page)
>>>>> https://www.springer.com/fr/book/9781493988488 (ade4 Book)
>>>>> https://pbil.univ-lyon1.fr/JTHome/Biblio/ThioulouseEB2021.pdf (Evol. Biol. paper)
>>>>> _______________________________________________
>>>>> 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
>>>>
>>
>