[RESOLVED] read only alias to a pointer

[Muthuveerappan]

Thanks all for all your valuable inputs, it has helped me understand better.

Thanks JVene, I was able to understand what your program was doing.
It was an interesting idea, and I certainly didn't think from that angle.
In the process I learned the conversion operator, never knew that existed. Thanks.

Just one point, actually with the program (constalias 2nd version), we wouldn't be able to "declare" a read only alias.

We would be stuck at the same point because we were attempting the following :

The conversion operator returns the following type:
const int* const &

This is done is by returning a variable of the type int*

so effectively it is equivalent to:

int* p1;
const int* const & p2 = p1;

This is exactly where the gcc compiler seems to differ from MSVC.
And therefore the conversion operator actually returns a temporary address and not the way we intended.
Hence we get that warning "warning: returning reference to temporary" while compiling.

The more I look at it the more it seems like a certain compiler bug.
The reason I say that is because, "const int* const &" is meant to be an alias (besides other restrictions it is supposed to impose such as not allowing int* and int** to be modified). But in gcc it simply isn't an alias !

the following would work, till gcc bug is reported and gets fixed:

#include<iostream>
using namespace std;

int main()
{
    system("clear");

    int v1 = 10; 

    int* p1 = &v1;

    const int* const * pt = &p1;
    const int* const & pa = *pt;

    cout << "&v1 = " << &v1 << "\tv1 = " << v1 << endl;
    cout << "&p1 = " << &p1 << "\tp1 = " << p1 << "\t*p1 = " << *p1 << endl;
    cout << "&pa = " << &pa << "\tpa = " << pa << "\t*pa = " << *pa << endl;
        
    return(0);
}

As you suggested the same could be implemented in the form of a template class to cater to a generic solution.

Thanks again, for all your thoughts, much appreciated !!!