我正在尝试在 R 包中使用 OpenCV 中的一些代码,使用 Rcpp 来构建包。当我在我的机器上编译 c 代码时,它工作正常。
例如,我在本地使用以下语法来编译 facedetect.cpp 代码:
g++ `pkg-config --cflags opencv` facedetect.cpp -o facedetect `pkg-config --libs opencv`
但是,当我尝试使用以下命令将其包含在我的包中时:
R CMD SHLIB facedetect.cpp -o facedetect
在我的 makevars 文件中定义了以下内容:
PKG_CPPFLAGS= `$(R_HOME)/bin/Rscript -e 'Rcpp:::CxxFlags()'`
PKG_LIBS = `$(R_HOME)/bin/Rscript -e "Rcpp:::LdFlags()"`
PKG_CXXFLAGS= `pkg-config --cflags opencv` `pkg-config --libs opencv`
R 执行以下操作:
g++ -arch x86_64 -I/Library/Frameworks/R.framework/Resources/include -I/Library/Frameworks/R.framework/Resources/include/x86_64 `pkg-config --cflags opencv` `pkg-config --libs opencv` `/Library/Frameworks/R.framework/Resources/bin/Rscript -e 'Rcpp:::CxxFlags()'` -I/usr/local/include -fPIC -g -O2 -c facedetect.cpp -o facedetect.o
这给了我以下错误消息:
i686-apple-darwin10-g++-4.2.1: -lopencv_core: linker input file unused because linking not done
i686-apple-darwin10-g++-4.2.1: -lopencv_imgproc: linker input file unused because linking not done
i686-apple-darwin10-g++-4.2.1: -lopencv_highgui: linker input file unused because linking not done
i686-apple-darwin10-g++-4.2.1: -lopencv_ml: linker input file unused because linking not done
i686-apple-darwin10-g++-4.2.1: -lopencv_video: linker input file unused because linking not done
i686-apple-darwin10-g++-4.2.1: -lopencv_features2d: linker input file unused because linking not done
i686-apple-darwin10-g++-4.2.1: -lopencv_calib3d: linker input file unused because linking not done
i686-apple-darwin10-g++-4.2.1: -lopencv_objdetect: linker input file unused because linking not done
i686-apple-darwin10-g++-4.2.1: -lopencv_contrib: linker input file unused because linking not done
i686-apple-darwin10-g++-4.2.1: -lopencv_legacy: linker input file unused because linking not done
i686-apple-darwin10-g++-4.2.1: -lopencv_flann: linker input file unused because linking not done
g++ -arch x86_64 -dynamiclib -Wl,-headerpad_max_install_names -undefined dynamic_lookup -single_module -multiply_defined suppress -L/usr/local/lib -o facedetect facedetect.o -I/opt/local/include/opencv -I/opt/local/include -L/opt/local/lib -lopencv_core -lopencv_imgproc -lopencv_highgui -lopencv_ml -lopencv_video -lopencv_features2d -lopencv_calib3d -lopencv_objdetect -lopencv_contrib -lopencv_legacy -lopencv_flann -F/Library/Frameworks/R.framework/.. -framework R -Wl,-framework -Wl,CoreFoundation
我不明白这些错误消息,因为我没有足够的 C++ 经验。有谁知道如何让 R 像我的本地 g++ 编译器那样编译 C++ 代码?我不确定“-c”标志是否是问题......不幸的是,我无法通过谷歌或编写 R 扩展手册找到答案。谢谢!