What does "Foo( Bar() );" mean ?

=======
Hi, I've read about "Foo x( Bar() );" in C++ FAQ LITE, section 10.19
http://www.parashift.com/c++-faq-lite/ctors.html

And then I've played with similar "Foo( Bar() );" construct.
My question is: what does "Foo( Bar() )" really mean ??
See comments for details.

=======
// compiled and tested using gcc 4.1.2

#include <iostream>

using namespace std;

struct Bar
{
    Bar() { cout << "Bar::Bar()" << endl; }
};

struct Foo
{
    Foo(const Bar&) { cout << "Foo::Foo(const Bar&)" << endl; }
    ~Foo() { cout << "Foo::~Foo()" << endl; }
};

int main()
{
    // doesn't call Foo constr - it declares "foo" as a function
    Foo foo( Bar() );

    // when You uncomment the following line,
    // You'll get a link error: undefined reference to `Bar()'
    // You don't get this error when the rest of main() is commented
out

    // Foo( Bar() );

    // calls Foo constr and then f, gives a warning: "taking address
of temporary"
    & Foo( Bar() );

    // the same line as before, but here it's accepted by the compiler
    // it still doesn't call Foo constr, though

    Foo( Bar() );

    // gives a warning: "statement has no effect"
    // - so "Foo( Bar() );" should be a STATEMENT too
    int( double() );

    return 0;
}

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