How to enforce move semantics when a vector grows?

Question

I have a std::vector of objects of a certain class A. The class is non-trivial and has copy constructors and move constructors defined.

Answer 1

Interestingly, gcc 4.7.2's vector only uses move constructor if both the move constructor and the destructor are noexcept. A simple example:

struct foo {
    foo() {}
    foo( const foo & ) noexcept { std::cout << "copy\n"; }
    foo( foo && ) noexcept { std::cout << "move\n"; }
    ~foo() noexcept {}
};

int main() {
    std::vector< foo > v;
    for ( int i = 0; i < 3; ++i ) v.emplace_back();
}

This outputs the expected:

move
move
move

However, when I remove noexcept from ~foo(), the result is different:

copy
copy
copy

I guess this also answers this question.