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mwreese@austin.rr.com · Guest

In trying to create a class that has both a copy constructor and a
constructor that takes a functor for initialization, I get a compile
error. It seems that the compiler tries to use the constructor that
takes the functor for copy purposes rather than the copy constructor.
Is there any way to get around this problem? Below is a simple example
that illustrates the problem. Thanks for all your help.

--Michele

I'm using gcc 3.4.1 and the error message is:

cd /home/r3aajx/work/adl/
g++ -g -Wall example2.C -o out
Reading site .bashrc
Reading site .bash.interactive
example2.C: In constructor `FooImpl<S>::FooImpl(R&) [with R = Foo<20>,
int S = 20]':
example2.C:38: instantiated from `Foo<S>::Foo(R&) [with R = Foo<20>,
int S = 20]'
example2.C:49: instantiated from here
example2.C:11: error: no match for call to `(Foo<20>) ()'

Compilation exited abnormally with code 1 at Thu Mar 24 16:16:06

#include <iostream>
using namespace std;

template <int S>
class FooImpl {
public:
FooImpl() : _data(0), _size(S) {};
FooImpl(const FooImpl<S>& f) : _data(f._data), _size (f._size) {}
template <typename R>
FooImpl(R &r) { r(); }

void print(ostream &o) {
o << _data << "(" << _size << ")";
};
private:
unsigned _data;
unsigned _size;
};

class my_functor {
public:
void operator ()() { cout << "in functor " << endl; }
};

template class Foo : private FooImpl<S> {
public:
typedef FooImpl<S> _Base;

Foo () {};
Foo (const Foo<S> &x) : _Base(x) {};
template <typename R>
Foo (R &r) : _Base(r) {}
};

int main (int argc, char **argv)
{
my_functor mf;
Foo<20> f1(mf);

Foo<20> f2(f1);
return 0;
}

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Antoun Kanawati · Guest

[email]mwreese (AT) austin (DOT) rr.com[/email] wrote:

Marco Jez · Guest

<mwreese (AT) austin (DOT) rr.com> ha scritto nel messaggio
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