Undefine reference of <function name>

Question

When I've try to compile program (test for my lib) I've got undefined reference of for every called method. I've read answers on "gcc undefined reference to", but it has not help. PS I using: Debian 7.2.0 and C++11 standart.

#include <RFw/String.hpp>
#include <stdio.h>
using namespace RFw;

int main() {
Array<char> _arr_ (5);

_arr_[0] = 'b';
_arr_[1] = 'c';

printf("%c%c\n", _arr_[0], _arr_[2]);

printf(RFw::getVersion());

return 0;
}

Makefile target:

test:
    c++ test.cpp -I./include-core/ -o bin/test -L./bin -l${core_NAME_ROOT}

Console output:

test.cpp:13:9: warning: format string is not a string literal (potentially insecure) [-Wformat-security]
        printf(RFw::getVersion());
               ^~~~~~~~~~~~~~~~~
1 warning generated.
/tmp/test-lxdZF4.o: In function `main':
test.cpp:(.text+0x20): undefined reference to `RFw::Array<char>::Array(int)'
test.cpp:(.text+0x33): undefined reference to `RFw::Array<char>::operator[](int)'
test.cpp:(.text+0x54): undefined reference to `RFw::Array<char>::operator[](int)'
test.cpp:(.text+0x75): undefined reference to `RFw::Array<char>::operator[](int)'
test.cpp:(.text+0x99): undefined reference to `RFw::Array<char>::operator[](int)'
test.cpp:(.text+0xff): undefined reference to `RFw::Array<char>::~Array()'
test.cpp:(.text+0x11a): undefined reference to `RFw::Array<char>::~Array()'
./bin/libregemfw0.1-core.so: undefined reference to `RFw::Array<char>::operator[](int) const'
./bin/libregemfw0.1-core.so: undefined reference to `RFw::Array<char>::Array(int)'
./bin/libregemfw0.1-core.so: undefined reference to `RFw::Array<char>::getLength() const'
./bin/libregemfw0.1-core.so: undefined reference to `RFw::Exception::onThrow()'
./bin/libregemfw0.1-core.so: undefined reference to `RFw::Array<char>::resize(int)'
./bin/libregemfw0.1-core.so: undefined reference to `RFw::Array<char>::addElementOnEnd(char)'
./bin/libregemfw0.1-core.so: undefined reference to `vtable for RFw::Object'
./bin/libregemfw0.1-core.so: undefined reference to `typeinfo for RFw::Object'
./bin/libregemfw0.1-core.so: undefined reference to `RFw::Object::~Object()'
./bin/libregemfw0.1-core.so: undefined reference to `RFw::Array<char>::~Array()'
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [test] Ошибка 1

Answer 1

The problem is that

c++ test.cpp -I./include-core/ -o bin/test -L./bin -l${core_NAME_ROOT}c++ test.cpp -I./include-core/ -o bin/test -L./bin -l${core_NAME_ROOT}

will first process the library and then your .cpp file. When processing a library, referenced symbols are resolved ("linked") and all unresolved symbols in the library that aren't needed are thrown away. That means that as soon as your .cpp file is being processed, these symbols are already rejected. You have the library twice in your command line, but the second one is being ignored since the library was already processed.

You should always put the libraries (once) at the end of the compiler command line:

c++ test.cpp -I./include-core/ -o bin/test test.cpp -L./bin -l${core_NAME_ROOT}