why std::unique_ptr vector gets invalid pointer exception

Question

I wrote simple code to help me understand smart pointers:

string s = \"str\";
vector > pv ;

pv.push_back(unique_ptr         


        

Answer 1

Your string is being destructed twice - once when your pv goes out of scope and is deleted, freeing all its contained unique_ptr elements, and once when s goes out of scope.

To use a vector of unique pointers (or to use unique pointers in general), it is essential that they are not aliased. So you could write:

auto *s = new std::string("str");
pv.push_back(std::unique_ptr(s));
// do not write "delete s" anywhere...

Or, simpler and safer:

pv.push_back(std::make_unique("str")); // make_unique is C++14

Or even:

std::unique_ptr p{new std::string("str")};
pv.push_back(std::move(p));
// Do not attempt to use p beyond this point.