En/Disable Group Storage

These are responsible for switching the memory for all variables in a group on or off. They should return the former state, e.g. if the group already has storage assigned, they should return 1.

In our simple example above, the enabling routine would look something like

int SimpleEnableGroupStorage(cGH *GH, const char *groupname)
{

  extension = (struct SimpleExtension *)GH->extensions[SimpleExtension];

  if(extension->data[first][0][0] == NULL)
  {
    for(var = first; var <= last; var++)
    {
      allocate memory for all time levels;
    }
    retcode = 0;
  }
  else
  {
    retcode = 1;
  }

  return retcode;
}

The disable function is basically the reverse of the enable one.

The QueryGroupStorage function basically returns true or false if there is storage for the group, and the ArrayGroupSize returns the size of the grid function or array group in a particular direction.