Bad initialisation of std::vector ?

Question

This is how I declare my vector :

  std::vector <Link *> _components;

Link is this structure :

  struct Link
  {
    size_t targetPin;
    nts::IComponent *component;
  };

First to initialise it I do

  this->_components.reserve(2);

Then, when this instruction happen, it segfault

  this->_components[0]->component = this;

Got an idea ?

Change to `this->_components.resize(2);`. – πάντα ῥεῖ Feb 19 '16 at 17:12 — πάντα ῥεῖ, Feb 19 '16 at 17:12
Why `std::vector` and not `std::vector`? – GManNickG Feb 19 '16 at 17:14 — GManNickG, Feb 19 '16 at 17:14

kfsone · Accepted Answer · 2016-02-19T17:14:26.653

2

Reserve expands the capacity of the vector, it does not actually increase the size, and accessing a member beyond size is illegal.

this->_components.resize(2);

is what you appear to need.

If your vector has a fixed size of 2, you may want to consider using std::array instead.

--- EDIT ---

Your second problem is that you haven't assigned a Link* to any of the members. They're null pointers.

You may want std::vector<Link> instead of std::vector<Link*> unless you have Link objects to populate the vector with pointers to.

edited Feb 19 '16 at 17:14

answered Feb 19 '16 at 17:13

kfsone

I already tried it , it doesn't works either. – Dimitri Danilov Feb 19 '16 at 17:14
Yeah, I just re-read the question, see the edit. – kfsone Feb 19 '16 at 17:14
I think it got closed *because* other people missed that nuance too, it's the same one that was tripping you up, easy to miss :) – kfsone Feb 19 '16 at 17:17

1 Answers1