How to disallow temporaries

Question

For a class Foo, is there a way to disallow constructing it without giving it a name?

For example:

Foo(\"hi\");

And only allow it i

Answer 1

Declare one-parametric constructor as explicit and nobody will ever create an object of that class unintentionally.

For example

class Foo
{
public: 
  explicit Foo(const char*);
};

void fun(const Foo&);

can only be used this way

void g() {
  Foo a("text");
  fun(a);
}

but never this way (through a temporary on the stack)

void g() {
  fun("text");
}

See also: Alexandrescu, C++ Coding Standards, Item 40.