Re: [Boost-users] boost::lambda library, error with << operator (on g++ with SGI STL)

From: Kirit Sælensminde (kirit.saelensminde_at_[hidden])
Date: 2007-07-10 00:21:34

Maciek Godek wrote:
>   function<void (int, int)> f =
>     if_(_1 == _2) [
>             cout << cref("arguments are equal\n")
>     ].else_[
>             cout << cref("arguments differ\n")
>     ];
> 
>   f(1, 1);
>   f(1, 2);
> }
> On g++ 3.3.4 I got a (scarcely readable) error that std::ios_base copy
> constructor is private (the more recent compiler gave much more trashy
> output, but I've infered that the reason is probably the same).

I think you need to surround the cout with boost::ref, i.e. boost::ref( 
cout ). The lambda takes a copy of its argument, and you  want to make 
sure that it uses the reference instead.

K