Deleting a function is a C++11 feature:
The common idiom of “prohibiting copying” can now be expressed
directly:class X { // ... X& operator=(const X&) = delete; // Disallow copying X(const X&) = delete; };
[…]
The “delete” mechanism can be used for any function. For example, we
can eliminate an undesired conversion like this:struct Z { // ... Z(long long); // can initialize with an long long Z(long) = delete; // but not anything less };