Getting symbols error: 'ld: symbol(s) not found'

Question

I'm trying to execute this code, but I'm getting the symbol error of the title:

configfile.cpp:

#include "configFile.h"
#include <iostream>
#include <sstream>
#include <fstream>
#include <cstdlib>
#include <stdexcept>
#include <map>

configFile* configFile::getInstance(){
    pinstance = new configFile();
    return pinstance;
}

configFile::configFile(){
    filename = "/Users/myfolder/NetBeansProjects/Oier_2/config.cfg";
}

void configFile::setConfigFileName(std::string s){
    filename = s;
}

float* getConfiguration(std::string type, int size) {
    std::string data[size];
    std::string line;
    std::ifstream myfile("/Users/myfolder/NetBeansProjects/Oier_2/config.cfg");

    while (std::getline(myfile, line)) {
            std::istringstream is_line(line);
            std::string key;
            if (std::getline(is_line, key, '=')) {
                if(key.compare(type) == 0){
                    for(int i=0; i<size;i++){
                        std::getline(is_line,data[i],',');
                    }
                }
            }
        }

    float *fdata;
    for(int i=0;i<size;i++){
        fdata[i] = (float)atof(data[i].c_str());
    }
    return fdata;
}

And configFile.h:

#include <string>

#ifndef CONFIGFILE_H
#define CONFIGFILE_H

class configFile {

private:
    static configFile* pinstance;
    static std::string filename;    
public:
    static configFile* getInstance();
    void setConfigFileName(std::string s);
    float* getConfiguration(std::string type, int size);
protected:
    configFile();
    configFile(const configFile& orig);

};

#endif  /* CONFIGFILE_H */

The symbols error I'm having:

Undefined symbols: "configFile::filename", referenced from: configFile::configFile()in configFile.o configFile::configFile()in configFile.o configFile::setConfigFileName(std::basic_string, std::allocator >)in configFile.o
"configFile::pinstance", referenced from: configFile::getInstance() in configFile.o
configFile::getInstance() in configFile.o "configFile::getConfiguration(std::basic_string std::char_traits, std::allocator >, int)", referenced from: _main in main.o
ld: symbol(s) not found
collect2: ld returned 1 exit status

If it's necessary: main.cpp:

#include <cstdlib>
#include <stdio.h>
#include <iostream>
#include <string.h>
#include <stdlib.h>
#include <limits.h>
#include <algorithm>
#include "configFile.h"

using namespace std;

int main(int argc, char** argv) {
    configFile* cfg = configFile::getInstance();    

    string type = "tiempo";
    float* tiem = cfg->getConfiguration(type,3);

    for(int i=0; i< 3;i++){
        printf( " %f ", tiem[i]);
    }
}

I'm running a MaxOSX 10.6.8. Thanks in adavance

Answer 1

These two areas are the issue:

configFile::configFile(){
    filename = "/Users/myfolder/NetBeansProjects/Oier_2/config.cfg";
}

void configFile::setConfigFileName(std::string s){
    filename = s;
}

You've declared filename as a static data member, so its name must always be configFile::filename. If you meant to use a data member, you can simply remove the static definition.

The difference between static and non-static data members is that with static, only one variable exists, whereas with a non-static data member there is an instance of this variable per-class. So in this case, the consequence is that with static, each instance of configFile would reference the same file path, whereas removing static would make each configFile own its own filename and so have its own file path.