Automatically check bounds in std::vector [duplicate]

Answer 1

If you use GCC (or MinGW) with libstdc++, #define _GLIBCXX_DEBUG will do what you want.

Or even better, define it with a flag: -D_GLIBCXX_DEBUG.

Answer 2

To me, this utility template seems to be so straight-forward that I'd expect it to exist

For gcc it does exist. gcc libstdc++ has a set of debug containers. For std::vector it has __gnu_debug::vector debug container. See documentation.

Answer 3

I don't think anything like this exists, but it's fairly easy to create:

template <class Container>
struct bound_checked : public Container
{
  using Container::Container;

  auto operator[] (typename Container::size_type i) -> decltype(this->at(i))
  { return this->at(i); }

  auto operator[] (typename Container::size_type i) const -> decltype(this->at(i))
  { return this->at(i); }
};

[Live example]

Note that the above actually uses a discouraged practice, namely public inheritance from standard containers (which are not designed for it). My understanding of your question was that this wrapper would be used in testing purposes only, which is fine. However, if you want this to remain in production and want to be on the very safe side, use non-public inheritance:

template <class Container>
struct bound_checked : private Container
{
  using Container::Container;

  auto operator[] (typename Container::size_type i) -> decltype(this->at(i))
  { return this->at(i); }

  auto operator[] (typename Container::size_type i) const -> decltype(this->at(i))
  { return this->at(i); }

  using Container::begin;
  using Container::end;
  using Container::at;
  using Container::insert;
  // ... you get the idea
};

Answer 4

Does it? If so, under which name?

I'm pretty sure it does exist. Many compilers enable std::vector<T>::at() as implementation for std::vector::operator[]() if a compiler intrinsic __DEBUG building macro is enabled.

Therefore I'd like to write my code using the [] operator, but at the same time have bounds checks enabled. After testing the code, it should be very easy to remove the bounds checks.

Regarding the naming, I'd say that's debug vs. release building. The checks will be removed when the code is compiled without the __DEBUG definition.