On 6 October 2016 at 12:19, Avraham Adler wrote: | Has anyone successfully created a package that uses Rcpp for C++ code | and which also has Fortran code? I'm experimenting with comparing | Fortran and C++ and if I could use Rcpp to handle the C++ portion, it | would reduce the steepness of the learning curve. | | However, I haven't had success. The following C++ and Fortran snippets | compile properly separately—the C++ as part of Rcpp and the Fortran | using R CMD SHLIB and dynload—and the R snippets call them properly, | but when I put both the .cpp and .f95 files in /src, I get the huge | error posted below the files. | | Am I missing something simple or will having C++ and Fortran code in | the same package prevent the use of Rcpp and require the old methods | of calling compiled code?
Avi, Take a look at my package 'htdp' for a complete example: https://github.com/jbuonagurio/RHTDP Specifically: src/Makevars src/RcppHTDP.cpp src/htdp/htdp.h src/htdp/README A few notes: 1. I have a single Fortran file with F95 INCLUDE statements to simplify the build, at the cost of incremental linking. You don't have to do this, see the 'matrix' package on CRAN for a more complex build example. 2. Set 'PKG_LIBS = $(FLIBS)' in Makevars to link the appropriate libraries (-lgfortran -lquadmath -lm). 3. Do not use Fortran I/O if you want your package on CRAN (e.g. WRITE, STOP). Use the R-only versions of error and warning (REXIT, RWARN). These are defined in src/main/xxxpr.f in the R sources. 4. This package will probably only work with gfortran, which exports all symbols with a trailing underscore by default. Make sure your function prototypes have the underscore in the header file, with extern "c". 5. A better and more interoperable way to call Fortran from C/C++ is to use ISO_C_BINDING, which lets you pass by value, set number of bytes for storage, etc. I originally set up this package to use ISO_C_BINDING, however I realized later that earlier versions of gfortran (before GCC 4.9.3) require explicit interfaces which I didn't want to bother with. You probably should. See this older commit for the ISO_C_BINDING version: <https://github.com/jbuonagurio/RHTDP/commit/5912279aa139b15baa435db2d6e6f78807a707a3> 6. Don't use .Fortran(). Call the Fortran code from C++, and let Rcpp attributes create the .Call() statements for you. Dirk/Kevin, please feel free to add/revise! Best, John Buonagurio _______________________________________________ Rcpp-devel mailing list Rcpp-devel@lists.r-forge.r-project.org https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel
