typedef [www.who.is.free.fr]

typedef is usefull to decribe new types :

typedef char* pchar;

typedef struct {
 int lenght;
 char* ptr;
} buffer_t;

But how to rewrite this without using typedef ?

typedef int vint2[[2]];

int fAllocTypedefPtr(vint2* & a  ) { //symbol is int (* &)[[2]]
a = new int[[1]][[2]];
a[[0]][[0]] = 2;  //ok
}

int f(int (*&a)[[2]]) { }  // for your curiousity

<Adrinael> boost::multi_array stores it in a contiguous array.

ARRAY COPY

I suppose that typedef C keyword dont get along with arrays :

please explain me this :

typedef float vfloat3[[3]];

int main() {
vfloat3 a= { 0, 1, 2 };
cout << a[[0]] << a[[1]] << a[[2]] <<endl; // ok : 012
vfloat3 b;
// b=a; // error: ISO C++ forbids assignment of arrays //gcc complain
return 0;
}

Of course if you replace vfloat3 by float3 , it does not make sense but why allowing typedef with arrays if you can not fully use them ?

ARRAY COPY CONSTRUCTOR NEEDED BY STL

Doesnt work better with C++ STL

#include <vector>
#include <iostream>
using namespace std;

typedef float vfloat3[[3]];

int main()
{

vfloat3 a= { 0, 1, 2 };
cout << a[[0]] << a[[1]] << a[[2]] <<endl; // ok : 012
vector<vfloat3> v;
cout<<v.size() <<endl; // ok : 0
v.push_back(a); //gives errors on compilation (g++ and msvc)
return 0;
}

/*

/usr/include/c++/3.3.1/bits/stl_vector.h:603:
instantiated from `void std::vector<_Tp, _Alloc>::push_back(const _Tp&)
[[with _Tp = float[[3]], _Alloc = std::allocator<float[[3]]>]]'

c:\program files\microsoft visual studio\vc98\include\xutility(39) :
error C2440: '=' : cannot convert from 'const float [[3]]' to 'float [[3]]'
      There is no context in which this conversion is possible
c:\program files\microsoft visual studio\vc98\include\vector(170) :
see reference to function template instantiation
'void __cdecl std::fill(float (*)[[3]],float (*)[[3]],const float (&)[[3]])' being compiled
c:\program files\microsoft visual studio\vc98\include\xutility(25) :
error C2106: '=' : left operand must be l-value
c:\program files\microsoft visual studio\vc98\include\vector(174) :
see reference to function template instantiation
'float (*__cdecl std::copy_backward(float (*)[[3]],float (*)[[3]],float (*)[[3]]))[[3]]' being compiled
c:\program files\microsoft visual studio\vc98\include\xmemory(34) :
error C2538: new : cannot specify initializer for arrays
c:\program files\microsoft visual studio\vc98\include\xmemory(66) :
see reference to function template instantiation
'void __cdecl std::_Construct(float (*)[[3]],const float (&)[[3]])' being compiled

/

<MooZ> RzR: push_back needs the = operator to be defined

<MooZ> so that's why u have an error
<MooZ> have u tried:
<MooZ> typedef vfloat3{
<MooZ>   union {
<MooZ>     float data[[3]];
<MooZ>   struct{ float x,y,z; };
<MooZ> };

<Doudou> (a propos de la page) le premier probleme, ca marche pas parce que un tableau C et C++ sur un type T est un "T const*" donc b = a ca merde
<Doudou> Le deuxieme, ca merde pour exactement pour la meme raison.
<Doudou> std::vector<T> a besoin que T soit "assignable", autrement dit que l'opérateur = soit valide, ce qui n'est pas le cas ici
<Doudou> std::list, par contre, a juste besoin d'un constructeur par copie. Donc ca marche ..