Re: copy ctor not called

[Jeroen Wijnhout <Jeroen.Wijnhout@kdemail.net>]

On Saturday 02 July 2005 09:17 pm, Travis Spencer wrote:
> On 7/2/05, Jeroen Wijnhout <Jeroen.Wijnhout@kdemail.net> wrote:
> > Consider a class with a copy constructor:
> >
> > class A
> > {
> > public:
> >   A(int i) : m_i(i)
> >   {
> >     cout << "A(int i)" << endl;
> >   }
> >
> >   A(const A &a)
> >   {
> >     cout << "A(const A &a)" << endl;
> >     m_i = a.i();
>
> This doesn't compile:
>
> copyctor.cpp: In copy constructor `A::A(const A&)':
> copyctor.cpp:16: error: passing `const A' as `this' argument of `int
> A::i()' discards qualifiers

Sorry about that, should have been:
int i() const
{
  return m_i;
}

> > Now, I understand that gcc optimizes away the copy constructor and
> > interprets the code as:
> > A a(2);
> >
> > However, is there a way to force gcc to use the copy constructor?
>
> If I were a jerk, this is where I would say to RTFM, but since I'm not
> I'll kindly point out the -fno-elide-constructors flag:

Actually I did, missed that, but thanks for pointing it out. ;-)

> > CXXFLAGS=-fno-elide-constructors g++ -fno-elide-constructors 
> > copyctor.cpp  -o copyctor ./copyctor

Indeed this works as it should.

best,
Jeroen
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