Read the Posting Guide. This will tell you at least two important things: 1) Post using plain text. HTML mangles code.
2) Interfacing R with other languages is off-topic on this list. There are other lists where such issues are on-topic. Your post is a bit like walking into a bowling alley and asking if anyone there can solve your chess problem... someone might be able to, but it isn't very efficient and disturbs the bowlers unnecessarily. -- Sent from my phone. Please excuse my brevity. On July 22, 2016 11:12:57 AM PDT, "Ganz, Carl" <carlg...@ucla.edu> wrote: >Hello everyone, >I am attempting to link to a C library named libxlsxwriter >(http://libxlsxwriter.github.io/) that creates and styles XLSX files, >but after several days of repeatedly reading "Writing R Extensions", >and I am stuck and hoping someone can help me. >The C library is easy to use and works with C++ as you would expect. >For example, here is test.cpp: >#include <xlsxwriter.h> >int main() { > lxw_workbook *workbook = workbook_new("myexcel.xlsx"); > lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL); > int row = 0; > int col = 0; > worksheet_write_string(worksheet, row, col, "Hello me!", NULL); > return workbook_close(workbook); >} >To compile this I need to run the makefile in the libxlsxwriter folder, >which compiles the libxlsxwriter library, and then call: >cc test.cpp -o test -Ipath.to.xlsxwriter.h path.to.libxlsxwriter.a -lz >This generates an executable that creates an excel document. I >understand this command says to compile test.cpp and specifies where to >search for headers, and what libraries to link to so to get this to >work with R all I should need to do is make the library, point to the >header, and link to the .a file. >To get this to work with R, I created a libxlsxwriter folder in my /src >folder with the libxlsxwriter library in it, and added this makevars to >my /src: >PKG_CFLAGS= ># specify header location >PKG_CPPFLAGS=-Ilibxlsxwriter/include ># specify libs to link to >PKG_LIBS=liblsxwriter/lib/libxlsxwriter.a -lz ># make libxlsxwriter >libxlsxwriter/lib/libxlsxwriter.a: > cd libxlsxwriter;$(MAKE) > >When I build the package I can see that this runs the makevars, and >generates the .a and .dll files in libxlsxwriter. I get no errors >associated with headers or the libraries so I thought I would be good >to go, but I can't seem to get anything to run. >Here is my test.cpp code I am trying to run in R with Rcpp: >#include <Rcpp.h> >#include <xlsxwriter.h> >using namespace Rcpp; >//' @useDynLib libxlsxwriter >//' @export >//' @import Rcpp >// [[Rcpp::export]] >void test() { > lxw_workbook *workbook = workbook_new("myexcel.xlsx"); > lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL); > int row = 0; > int col = 0; > worksheet_write_string(worksheet, row, col, "Hello me!", NULL); > workbook_close(workbook); >} >I am fairly certain I am doing something wrong with my makevars that is >preventing test.cpp from being compiled. I tried running the makevars >for libxlsxwriter from the command line and then building using just >this makevars: >PKG_CFLAGS= ># specify header location >PKG_CPPFLAGS=-Ilibxlsxwriter/include ># specify libs to link to >PKG_LIBS=liblsxwriter/lib/libxlsxwriter.a -lz >I see the .o files for test.cpp being built, which is a good sign, and >indicates there was a problem with my previous makevars, but I get >errors saying undefined reference for all the functions from >libxlsxwriter, so clearly thinks aren't linking like I need them to. I >am out of ideas at this point, so any guidance would be greatly >appreciated. >A github repo with my code is here: >https://github.com/carlganz/lwritexlsx >I was using this webpage as a guide for how to include a C library in >an R package: http://mazamascience.com/WorkingWithData/?p=1151 >Kind Regards, >Carl Ganz > > [[alternative HTML version deleted]] > >______________________________________________ >R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >https://stat.ethz.ch/mailman/listinfo/r-help >PLEASE do read the posting guide >http://www.R-project.org/posting-guide.html >and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
