I don't understand. none of the above seems to answer the question of what you have to do in order to compile a c++ program or library from command line. For a start if you search the man pages for information using: man c++ or man clang or man clang++ it brings up the page for "clang" which it says on that page is the compiler for c, c++ and objective-c here's my command for building object file for a library and the command i am using to try to create and dynamic link library clang -g -fPIC -mdynamic-no-pic -c slabhra.cpp -o slabhra.o 0>>./tmp 1>>./tmp 2>>./tmp clang -mdynamic-no-pic -target arm64 -dylib -o libarmlann.dylib slabhra.o 0>>./tmp 1>>./tmp 2>>./tmp Undefined symbols for architecture arm64: "typeinfo for char const*", referenced from: slabhra::getCharStrAtLocation(int) in slabhra.o slabhra::getCharStrAtLocation(int) in slabhra.o "operator new[](unsigned long)", referenced from: slabhra::slabhra() in slabhra.o slabhra::slabhra() in slabhra.o slabhra::slabhra(char*) in slabhra.o slabhra::slabhra(char*) in slabhra.o slabhra::slabhra(char const*) in slabhra.o slabhra::slabhra(char const*) in slabhra.o slabhra::operator=(char*) in slabhra.o ... "___cxa_allocate_exception", referenced from: slabhra::getCharStrAtLocation(int) in slabhra.o slabhra::getCharStrAtLocation(int) in slabhra.o "___cxa_throw", referenced from: slabhra::getCharStrAtLocation(int) in slabhra.o slabhra::getCharStrAtLocation(int) in slabhra.o "___gxx_personality_v0", referenced from: /Volumes/External SSD/valuable/foinse/cód/armlann/slabhra.o "_main", referenced from: ld: symbol(s) not found for architecture arm64 clang: error: linker command failed with exit code 1 (use -v to see invocation) clang: error: linker (via gcc) command failed with exit code 1 (use -v to see invocation) I am expecting an INCLUDE path update or an install of extra code/object/libraries... i.e. i'm not sure what they mean by symbols. Thanks in advance for looking at my issue...