CODEWITHSUNDEEP
c++oopinheritancepolymorphism
GalB1t
GalB1t

Reputation: 265

c++ member function polymorphism issue

I'm experiencing troubles with c++ inherrited member function, look at the following code: 

binIO_t wtest(path, mode);
const void* Buff = "abcd";
wtest << Buff, 1; //no operator found
wtest.virtIO_t::operator<<(Buff), 1; //works fine

Exact compiler error is:

Error 1 error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'void *' (or there is no acceptable conversion) ...

I'm surly missing some subtle decleration yet I fail to find it.

my superclass.h is:

#pragma once
#include <string>
#include <iostream>
#include <fstream>
#include <stdio.h>

using namespace std;

class virtIO_t{
private:
    virtIO_t();

public:
    virtIO_t(string filePath, string fileMode);
    ~virtIO_t();

    virtual virtIO_t& operator >> (void* Buf);
    virtual virtIO_t& operator << (const void* Buf);

    virtual virtIO_t& operator << (const char val) = 0;
    virtual virtIO_t& operator >> (char &val) = 0;
};

and the superclass.cpp is:

#include "stdafx.h"
#include "virtIO_t.h"

virtIO_t::virtIO_t()
{
}

virtIO_t::~virtIO_t()
{
    ...
}

virtIO_t::virtIO_t(string filePath, string fileMode){
...
}


virtIO_t& virtIO_t::operator << (const void* Buff){
    ...
}
virtIO_t& virtIO_t::operator >> (void* Buff){
    ...
}

and the sub.h is:

#pragma once
#include "virtIO_t.h"

class binIO_t : public virtIO_t{

public:
    binIO_t(string filePath, string mode);

    virtIO_t& operator << (const char val);
    virtIO_t& operator >> (char &val);

and the sub.cpp is:

#include "stdafx.h"
#include "binIO_t.h"

binIO_t::binIO_t(string filePath, string mode) : virtIO_t(filePath, (string(mode) + "b").c_str()){}

    virtIO_t& binIO_t::operator << (const char val){
    ...
    }

    virtIO_t& binIO_t::operator >> (char &val){
    ...
    }

Upvotes: 1

Views: 86

Answers (1)

Hcorg
Hcorg

Reputation: 12178

binIO_t declares it's own operator<< which hides operator<<(void*) from base class. Try using virtIO_t::operator<< directive or explicitly define operator<<(void*) in biunIO_t.

Also: , 1 does nothing.

Upvotes: 1

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