As an example consider the following program
 
#include <iostream>
#include <functional>
void f( std::reference_wrapper<int> , std::reference_wrapper<int> )
{
    
}
void f( int, int )
{
    
}
int main() 
{
    int i = 10;
    std::reference_wrapper<int> ri( i );
    
    f( i, ri );
    f( i, ri );
    
    return 0;
}
 
Here is an ambiguity in calling the function f.
You can meet me at http://cpp.forum24.ru/ or www.stackoverflow.com or http://ru.stackoverflow.com
 
 
Пятница, 26 марта 2021, 21:48 +03:00 от Vladimir Grigoriev via Std-Discussion <std-discussion@lists.isocpp.org>:
 
I am sorry. I made an incorrect resume about the error. Nevertheless the questions about implicit constructor are actual.
 
 
 
 
Пятница, 26 марта 2021, 21:33 +03:00 от Vladimir Grigoriev via Std-Discussion <std-discussion@lists.isocpp.org>:
 
Consider the following code snippet.
 
    int x = 10;
    std::reference_wrapper<int> rx( x );
    std::swap( rx, x );
 
The compiler will issue an error because either rx can be implicitly converted to the type int or x can be implicitly converted to the type std::reference_wrapper<int>.
 
So a pair of questions are arising.
 
Should the constructor of the class template std::reference_wrapper be explicit?
What is the reason that the constructor is implicit? Is that so necessary?
 
 
 
--
Std-Discussion mailing list
Std-Discussion@lists.isocpp.org
https://lists.isocpp.org/mailman/listinfo.cgi/std-discussion