Why is std::string and std::vector not being passed to my constructor how I would expect? [duplicate]

This question already has an answer here:

This is my error when trying to compile:

Undefined symbols for architecture x86_64:
"Model::Model(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::vector<int, std::__1::allocator<int> >)", referenced from: ____C_A_T_C_H____T_E_S_T____4() in tests.cpp.o


I have read that std::string is a typedef of std::basic_string and I'm guess that std::vector is a typedef of... std::vector and std::allocator? or something...

Anyway. I have a Settings class that holds my settings and a Model class that contains my model. The code I am attempting to run is as below, and I am unable to compile it. the issue is with it not recognising my model constructor.

Settings s = Settings("../config/settings.json");
std::string mf = s.get_model_file();
std::vector<int> vec = s.get_input_shape();
Model m = Model(mf, vec);


For reference here is my Model class header:

class Model {
public:
Model(std::string model_file, std::vector<int> input_shape);
~Model();
double* get_ref_to_input_buffer();
std::string predict();

private:
std::string _model_file;
fdeep::model _model;

fdeep::shape3 _input_shape;
int _input_size;
double* _input_buffer;
fdeep::tensor3s _result;

void _load_model();
void _set_input_size(std::vector<int> input_shape);
void _set_input_shape(std::vector<int> input_shape);
void _create_input_buffer();
std::string _result_to_string();
};


and my Model class constructor:

Model::Model(std::string model_file, std::vector<int> input_shape) {
_model_file = model_file;
_load_model();
_set_input_size(input_shape);
_set_input_shape(input_shape);
}


These are the function being called in the constructor:

void Model::_load_model() { _model = fdeep::load_model(_model_file); }

void Model::_set_input_size(std::vector<int> input_shape) {
int total = 1;
for (std::vector<int>::iterator it = input_shape.begin();
it != input_shape.end(); ++it) {
total *= *it;
}
_input_size = total;
}

void Model::_set_input_shape(std::vector<int> input_shape) {
_input_shape = fdeep::shape3(input_shape[0], input_shape[1], input_shape[2]);
}


If anyone could point out where I'm going wrong or send me in the direction of what I need to read / learn that would be great. Thank you!

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

Model

_model

: _model(fdeep::load_model(model_file)

std::vector

typedef

2 Answers
2

According to http://www.cplusplus.com/forum/general/55587/

"Undefined Symbols" generally indicates a linking issue. Are you definitely linking correctly to the appropriate library?

Your code compiles fine. The linker then goes looking in the libraries for the right functions, and since you compiled for architecture x86_64, it looks for the right libraries, similarly compiled - and finds none. This suggests (unless you've simply forgotten to link to the 64 bit library) that you've got a 32 bit version of the library. Your choices are:

Model::Model(std::string model_file, std::vector<int> input_shape)

Model.cpp

By taking @Aconcagua 's advice I output the linker command from cmake using:

make tests VERBOSE=1

make tests VERBOSE=1

which gave me:

usr/bin/g++ -Wl,-search_paths_first -Wl,-headerpad_max_install_names CMakeFiles/tests.dir/tests.cpp.o CMakeFiles/tests.dir/__/Settings.cpp.o -o ../../../bin/tests

usr/bin/g++ -Wl,-search_paths_first -Wl,-headerpad_max_install_names CMakeFiles/tests.dir/tests.cpp.o CMakeFiles/tests.dir/__/Settings.cpp.o -o ../../../bin/tests

Noticing that this did not have a Model.cpp.o file I checked CMakeLists.txt and found:

Model.cpp.o

add_executable(tests tests.cpp ../Settings.cpp ../Model.hpp)

add_executable(tests tests.cpp ../Settings.cpp ../Model.hpp)

Note that for Model I have entered the header file not the source file. Changing it to this:

add_executable(tests tests.cpp ../Settings.cpp ../Model.cpp)

add_executable(tests tests.cpp ../Settings.cpp ../Model.cpp)

Fixed my problem.

Model::Model(std::string model_file, std::vector<int> input_shape)