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 };