Question

I am using forward declaration and now I am getting an error referring to the class that uses the forward declaration…so fInstance forward declares fConfig and then the Helper class (a namespace – used for global access to functions) – getting t

fConfig.h

#ifndef FCONFIG_H
#define FCONFIG_H

#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <sstream>
#include <string>
#include <cstring>
#include <sys/types.h>
#include <fcntl.h>
#include "JWDSFork.h"
//#include "fInstance.h"

using namespace std;

class fConfig
{
    private:
        pid_t pid, w;

    public:
        pid_t cPid;
        string name;

        int group;
        int instanceId;
        int numInstance;
        int tries;

        bool reply;
        bool debug;
        bool service;
        bool currentlyRunning;

        time_t startTime;
        time_t endTime;

        string path;

        fConfig();
        virtual ~fConfig();

        void start();
        string intToString(int);
        char* stringToChar(string);
};

#endif // FCONFIG_H

fInstance.h

#ifndef FINSTANCE_H
#define FINSTANCE_H

//#include "fConfig.h"
#include <vector>
#include <sys/types.h>
#include <string>

using namespace std;

class fConfig;


class fInstance
{
public:

    fConfig* config;
    pid_t pid;
    vector<string> notes;
    vector<time_t> times;

    fInstance();
    virtual ~fInstance();


};

#endif // FINSTANCE_H

Helper.h

#ifndef HELPER_H
#define HELPER_H

#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <string>
#include <cstring>
#include <vector>
#include <sstream>
#include <limits.h>
#include "fInstance.h"

using namespace std;

namespace Helper
{
    extern string APPDIR;

    bool errorCheck(int, char*);
    string charToString(char*, int);
    string longToString(unsigned long);
    bool Contains(vector<fInstance>, fInstance);
    string convertInt(int);
    string convertDouble(double);
    bool Read(int, char*, size_t);
    bool Write(int, char*, size_t);
};

#endif // HELPER_H

Helper.cpp

//Helper.cpp - function that causes a problem
#include "Helper.h"
namespace Helper
{

bool Contains(vector<fInstance> a, fInstance b)
    {
        for(unsigned int i= 0; i < a.size(); i++ )
        {
            if(a[i].config.name == b.config.name)
            {
                return true;
            }
        }

        return false;
    }
}

I am getting these errors

error: request for member ‘name’ in ‘a.std::vector<_Tp, _Alloc>::operator[] [with _Tp = fInstance, _Alloc = std::allocator<fInstance>](((long unsigned int)i))->fInstance::config’, which is of non-class type ‘fConfig*’

Answer 1

That’s a pretty unfriendly error message, but what it means is that the config member is a pointer, so you need to use the -> operator instead, ie.

 if(a[i].config->name == b.config->name)