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From: Khandelwal, Amit (amit.khandelwal_at_[hidden])
Date: 2008-06-13 10:56:42

I am trying to understand the details of boost function. Below is the
sample code that I am using. I was expecting the copy constructor to be
invoked once. However, I see that it is called four times. I am trying
to understand why does boost function need to have four copies of my
objects. I am using boost version 1_33_1.

Any thoughts/comments..

#include <iostream>
#include <stdlib.h>
#include <stdio.h>
#include "boost/function.hpp"
#include <map>

using namespace std;

class F
    F() {
        cout << "Cons" << endl;
    F(const F&) {
        cout << "Copy const" << endl;
    F& operator=(const F&) {
        cout << "operator = " << endl;
        return *this;
    int operator()(int a, int b) { cout <<" Sub" << endl; return a - b;

int main() {
     FUNC f = F();


Copy const
Copy const
Copy const
Copy const
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