joetekubi@yahoo.com wrote:[color=blue]
> hello all,
>
> while working with STL containers and various class
> composition, I can across a bug that I can't seem
> to find.
> When using a STL container in a derived class with
> composition, everything is good. If I use a pointer
> to a base class, the container fails with a SIGSEGV.
>
> TIA for any assistance.
>
> Example code is below
> Platform: Redhat 9, compile with "g++ -g test.cpp"
>
> //===================== cut here ================================
> #include <iostream>
> #include <set> // STL set container for nexthop IP addresses
>
> class Carbo
> {
> private:
> std::set < int > qtest;
> std::set < int >::iterator qiter; // destination address iterator
> public:
> Carbo();
> ~Carbo();
> void DoSomething();
> };
>
> class bread
> {
> private:
> Carbo *pcarbo;
> public:
> bread();
> ~bread();
> void DoBread();
> };
>
> class potato
> {
> private:
> Carbo mycarbo;
> public:
> potato();
> ~potato();
> void DoPotato();
> };
>
> using namespace std;
>
> Carbo::Carbo(){ cout << "Carbo ctor" << endl; }
>
> Carbo::~Carbo() { cout << "Carbo dtor" << endl; }
>
> void Carbo::DoSomething()
> {
> cout << "qtest before insert size = " << qtest.size() << endl;
> qtest.insert(2);
> qtest.insert(4);
> qtest.insert(14);
> qtest.insert(3);
> cout << "qtest after insert size = " << qtest.size() << endl;
> }
>
> bread::bread()
> {
> cout << "bread ctor " << endl;
> Carbo *pcarbo = new Carbo();
> }
>
> bread::~bread() { cout << " bread dtor" << endl; }
>
> void bread::DoBread() { pcarbo->DoSomething(); }
>
>
> potato::potato() : mycarbo() { cout << "potato ctor " << endl; }
>
> potato::~potato() { cout << " potato dtor" << endl; }
>
> void potato::DoPotato() { mycarbo.DoSomething(); }
>
>
> int main()
> {
> potato sweetpotato;
> sweetpotato.DoPotato(); // works ok, contained class
>
> bread wholewheat;
> wholewheat.DoBread(); // fails - pointer to class
>
> return 0;
> }[/color]
Sun's CC gives the follwing warning which is actually also your error...
"m.cc", line 54: Warning: pcarbo hides bread::pcarbo.
Tom
