Re: avoid implicit cctor call
Olaf wrote:
[..] here a more real problem of me:
#include <iostream>
#include <boost/utility.hpp>
using namespace std;
struct Foo : public boost::noncopyable {
Foo() { cout << " Foo()\n"; }
~Foo() { cout << "~Foo()\n"; }
//Foo( const Foo& ) { cout << " Foo(const Foo&)\n"; }
void set() const { cout << "Foo::set()\n"; }
};
struct Bar {
void set(const Foo& foo) const { foo.set(); }
};
int main()
{
Bar b;
b.set( Foo() );
Binding of a reference to a temporary *requires* the type to be
copy-constructible. You basically want to have your cake and eat
it too. Can't happen. Either make it copy-constructible, or
don't expect to be able to bind a const reference to a temporary.
}
$ LANG=en g++ cctor.cpp -o cctor && ./cctor
/usr/include/boost/noncopyable.hpp: In copy constructor
'Foo::Foo(const Foo&)':
/usr/include/boost/noncopyable.hpp:27: error:
'boost::noncopyable_::noncopyable::noncopyable(const
boost::noncopyable_::noncopyable&)' is private
cctor.cpp:6: error: within this context
cctor.cpp: In function 'int main()':
cctor.cpp:21: note: synthesized method 'Foo::Foo(const Foo&)' first
required here
Background more precise: Foo can have std::list<T> and function
pointer private data.
I can verify where the copy ctor is involved. Using the own (out
commented) Foo(const Foo&) did compile and run fine, but I'm not shure
about side effects here.
Side effects of what?
V
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