struct A : boost::noncopyable { int a; A(int _a) : a(_a) {} bool operator == (const A& r) const { return a == r.a; } };
int main() { boost::ptr_vector<A> pva; A a(0); std::find(pva.begin(), pva.end(), a); // ok boost::find(pva, a); // cause an error }
compiler: msvc2008
error message: e:\zxg\boost\range_ex\range.cpp(8) : error C2248: 'boost::noncopyable_::noncopyable::noncopyable' : cannot access private member declared in class 'boost::noncopyable_::noncopyable' d:\software\boost_1_37_0\boost\noncopyable.hpp(27) : see declaration of 'boost::noncopyable_::noncopyable::noncopyable' d:\software\boost_1_37_0\boost\noncopyable.hpp(22) : see declaration of 'boost::noncopyable_::noncopyable' This diagnostic occurred in the compiler generated function 'A::A(const A &)'
What's the benefit of providing assignment operator but blocking the copy-constructor?