HI Roman!

Thanks for your nice response!

I have just discovered another way.

Please give me your comments!

constant_type< const char[7] >::type _name(constant("value: "));

playing the same role of

boost::function<const char*()> _name = boost::lambda::constant("value: ");

I find both 2 nice ways of expressing constant string in a lamda expression.

Using the boost::function approach, some sample code can be written like the following
using round brackets next to _name variable.
std::for_each( myList.begin(),myList.end(),(
        std::cout << _name() << _1  ,
         _1 = 2
            ));

I find the approach using boost::function very nice since it provides
more the "genericity" feeling; you don't have to declare the size of the
string but it is enough const char*().
With the constant_type way it is possible to use _name as a common const variable without
using round brackets

std::for_each( myList.begin(),myList.end(),(
        std::cout << _name << _1  ,
         _1 = 2
            ));

This works fine provided that the size is correct; it is probably not always nice, 
but compiler will complain if the size is not correct i.e. if you use const char[6]
or if you use const char[8].
Now I am wondering which is the fastest approach. I guess that probably they are
the same.