[Boost-users] compile-time check that a member function exists

From: John Pretz (jpretz_at_[hidden])
Date: 2008-07-22 13:56:32

Hi,

I'm pretty new to boost.  I want to write some code with a compile-time 
check whether a member function exists or not.  The code below shows 
kinda what I need except I'd obviously like to avoid a specialized 
template for each class that I use.

Can anybody point me in the right direction?

Thanks,

John

****************************************
#include <iostream>

using namespace std;

struct WithMemberGo
{
 void Go() const {cout<<__PRETTY_FUNCTION__<<" going...."<<endl;}
};

struct WithoutGo
{
};

template <class T>
void CallGoIfItExists(const T& t){
 t.Go();
}

// I want to avoid having to specialize this function for every class 
without the
// right member function.
template <>
void CallGoIfItExists<WithoutGo>(const WithoutGo&){
 cout<<"not going anywhere...."<<endl;
}

int main(){
 WithMemberGo with;
 CallGoIfItExists(with);

 WithoutGo without;
 CallGoIfItExists(without);
}

-- 
John Pretz --  P-23, MS H803
Los Alamos National Lab  Los Alamos, NM 87545
Phone: [phone]  Fax: [phone]