Dynamic Array in c++ header file

Question

My cpp project has static 2d array in a header file but it causing chkstk error. I want to make it dynamic. Is it really possible to do with in the header as making changes to all parts of the project ( about 12000 lines code ) is difficult.

Answer 1

According to Dietmar's answer on a similar problem, most probably you need to put your static 2d array into a function so that it gets initialized in time.

Like this:

double**& my_array()
{
  static double** local = NULL;
  if(!local)
  {  
     // init your array here
  } 
  return local;
}

and you need to refer to your array like my_array() instead of my_array in the code.

EDIT:

For icepack's question: yeah, it looks rather strange (in my mind, a multi-array should be wrapped into a class anyway and then this would not happen). The reason for using this strange return type is the following:

// if you returned double** instead of double**&
my_array() = other_array; // would overwrite a temporary pointer
my_array(); // would be still the old array

---

If you use C++11, the cleanest solution is:

typedef std::array<std::array<double, second_dim>, first_dim> my_array_t;
my_array_t& my_array()
{
   static my_array_t local = initial_value();
   return local;
}

and you use my_array the same as before, with my_array().

Even if you don't use C++11, I suggest you define your own 2d_array class, it has no overhead over C arrays anyway, when you write it properly.