Pointer to object in std::vector

[elfeck]

Hello,

I store and access an object in a std::vector as follows:

//vector is a member variable
vector.push_back(MyObject());
//storing the pointer to the object in the vector
storePointer(&vector.at(0));

Will the pointer always (as long as I don't remove the object) be valid? Even if I add/remove other objects?

Thanks!

[Catfish4]

No. Adding objects may cause the vector to re-allocate its memory.

And here's proof:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

#include <iostream> #include <vector> int main() { std::vector<int> vi; for (int i=1; i <= 10; ++i) { vi.push_back(i); std::clog << &vi.at(0) << '\n'; } std::clog << std::endl; }

0x550ec8 0x550ee8 0x550ef8 0x550ef8 0x550f10 0x550f10 0x550f10 0x550f10 0x550f38 0x550f38

[elfeck]

Thanks for the quick reply!

[keskiverto]

Check out section Iterator validity in http://www.cplusplus.com/reference/vector/vector/push_back/ and in other standard container (e.g. std::vector) methods.

[Lowest0ne]

As a side, my_vector.data() returns the pointer also. No need for &my_vector.at(0)