[Development] Fornux C++ Superset

Phil Bouchard philippeb8 at gmail.com
Thu Apr 26 05:35:46 CEST 2018

On 04/25/2018 09:45 AM, Eric Lemanisser wrote:
> What about
> void foo(int (&array)[3])

This one works fine:

void foo(int (&array)[10])
     cout << __PRETTY_FUNCTION__ << endl;

int main()
     int array[10];


     return 0;

Correctly outputs:
void foo(const boost::node_proxy &, boost::root_array<std::vector<int>, 
10> (&))

> and
> template<int N>
> void foo(int (&array)[N]) ?

Since I just started testing C++98 as of last week, I haven't yet had a 
chance to test templates thoroughly. So this one is buggy and I'll have 
to fix it.

> Both of these functions make sure the caller and the callee use the same 
> array size at compile time. I don't see anybody giving away this kind of 
> security, especially fro functions called across translation units. Does 
> your system store the length of the array next to the pointer at runtime 
> ? What is the cost of this ?

root_array<> looks like this:

template <typename T, size_t S>
     class root_array : public boost::root_ptr<T>
         typedef boost::root_ptr<T> base;

         root_array(base const & p) : base(p)

         root_array(boost::node_proxy const & __y) : base(__y, "", 
boost::create<typename T::value_type>()(__y, S))


So it knows the length of the array at compile-time but it really 
creates a root_ptr pointing to a std::vector of size S allocated at 
runtime. This is the lowest common factor necessary to make a smooth 
conversion to a root_ptr.


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