[R-pkg-devel] how to call PROJ.4 C code in a package?
Yes, and a CRAN team member already suggested: "All CRAN build/test systems have proj4 installed (packages rgdal and proj need it) and it would have been better to link to libproj as those packages do."
If you're unsure how to do that, just look at the source for the proj4 package: https://github.com/cran/proj4/tree/master/src (that link is via the convenient github mirror) You'll need to mimic the makevars files. If that package doesn't do exactly what you need, you can use github search to look for other packages that use proj_api.h: https://github.com/search?q=user%3Acran+proj_api.h&type=Code Hadley