Re: Static intialization of flexible arrays in C++

[Eljay Love-Jensen <eljay at adobe dot com>]

Hi Nitin,

>Static initializations of a flexible array works with gcc but not with 
g++ . is this by design?

Yes, this is by design.  C++ does not have flexible arrays (or what I've 
heard called "stretchy arrays" or "stretchy buffers").  C++ has STL 
std::vector.

The stretchy buffer is a bad trick -- it's not portable, and may cause 
certain optimizations to fail is a bad way.

(I'm not sure if it is even legit C code.  Maybe it is with C99.  I dunno.)

A suggestion is to do the reverse:  specify the structure with the array 
given the maximum length, and allow allocations of less-than-maximum when 
used off the heap.  (There are caveats with this approach as well.)

struct flex_array_1000
{
  int A;
  int Data[1000];
};

Alternatively, you can use template structs to provide more exacting 
"hard-coded" arrays.

template <int Count>
struct flex_array
{
  int A;
  int Data[Count];
};

...and you can have the struct derived from a common base class if you need 
some sort of polymorphism.

HTH,
--Eljay