[ACCEPTED]-Passing "this" to a function from within a constructor?-this

Accepted answer

Score: 34

When you instantiate an object in C++, the 13 code in the constructor is the last thing 12 executed. All other initialization, including 11 superclass initialization, superclass constructor 10 execution, and memory allocation happens 9 beforehand. The code in the constructor 8 is really just to perform additional initialization 7 once the object is constructed. So it is 6 perfectly valid to use a "this" pointer 5 in a class' constructor and assume that 4 it points to a completely constructed object.

Of 3 course, you still need to beware of uninitialized 2 member variables, if you haven't already 1 initialized them in your constructor code.

Score: 4

You can find a good answer to this here (C++ FAQ).

All 9 inherited members and members of the calling 8 class are guaranteed to have been constructed 7 at the start of the constructor's code execution 6 and so can be referenced safely within it.

The 5 main gotcha is that you should not call 4 virtual functions on this. Most times I've 3 tried this it just ends up calling the base 2 class's function, but I believe the standard 1 says the result is undefined.

Score: 0

As a side-note on the presented code, I 3 would instead templatize the void*:

class Stuff
{
public:
    template <typename T>
    static void print_number(const T& t)
    {
        std::cout << t.number;
    }

    int number;

    Stuff(int number_)
    : number(number_)
    {
        print_number(*this);
    }
};

Then you'd 2 get a compile error if the type of t doesn't 1 have a number member.

Source: stackoverflow.com

[ACCEPTED]-Passing "this" to a function from within a constructor?-this

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[ACCEPTED]-Passing "this" to a function from within a constructor?-this

Who deletes the memory allocated during a "new" operation which has exception in constructor?

What is a copy constructor in C++?

Should I call the base class default constructor in the initialization list?

Dual emission of constructor symbols

Meaning of (QWidget *parent = 0) in constructor MyClass(QWidget *parent = 0);

Why doesn't this use of emplace_back with deleted copy constructor work?

Why explicitly call a constructor in C++

stl vector and c++: how to .resize without a default constructor?

A most vexing parse error: constructor with no arguments

Declaring an array inside a class, and setting its size with the constructor

Meaning of (QWidget parent = 0) in constructor MyClass(QWidget parent = 0);