Re: [Boost-users] [Serialization] is_serializable trait?

23 Jul 2007

      ...
Chris Fairles"  on Fri, 20 Jul 2007 18:03:18 
-0400
How can you determine (compile-time) that a class has a serialize 
function?
struct foo {
template <typename Archive>
void serialize (Archive &, const unsigned int);
};
"&foo::serialize" isn't a type and I can't figure out a way to make it
a type (besides a typedef in the class) and also a constant
expression.
Tried to play around with this as well but theres no substitution
failure here and static functions can't be constant expressions
(commonnnn c++0x!!)
struct serialize {
    template <typename T>
    static void value(T const&) { void(T::*f)(archive::xml_oarchive &,
const unsigned int) = &T::template serializearchive::xml_oarchive;
(void)f; }
};
Basically, in the code below I want to see "GoodGood" printed out and
the only thing I can change is Q.
struct A{
  void f(int,int){}
};
struct B{};
template 
struct Q{enum{value=false};};
template<class T> struct 
Q{enum{value=true};};
int main(){
  if(Q<A>::value) { cout << "Good";}
  if(!Q<B>::value){ cout << "Good";}
}
Help/hints/remotely possible?
You can try something like this.

#include <iostream>
#include <iomanip>

typedef char yes_type;

struct no_type
{
   char padding[8];
};

template <class T>
struct HasSerializeMember
{
    typedef void (T::*SerializationFun)(int &, unsigned);

    template <SerializationFun>
    struct A {};

    template <class Q>
    static yes_type Test(A<&Q::serialize>*);

    template <class Q>
    static no_type Test(...);

    static const bool value =
        sizeof(Test<T>(0)) == sizeof(yes_type);
};

struct A
{
    template <class Stream>
    void serialize(Stream & strm, unsigned version) {}
};

struct B
{
};

struct C
{
    void serialize() {}
};

int main()
{
    using namespace std;
    cout
        << boolalpha
        << HasSerializeMember<A>::value << '\n'  // true
        << HasSerializeMember<B>::value << '\n'  // false
        << HasSerializeMember<C>::value << endl; // false
}

Regards,
Roman Perepelitsa

Deutsche Bank Moscow
+7 (495) 660-74-08

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