Pure virtual function call

[Heather5]

I have a message "pure virtual function call" from MSVC 7.1 in release, when in debug it does not (as the code works correctly). Here is the offending code simplified:

class Base
{
public
    Base();
    virtual void doSmth() =0;
};
class Ext : public Base
{
    Ext();
    virtual void doSmth();
};
Base::Base()
{
    doSmth();
}
Ext::Ext() : Base()
{
}
void Ext::doSmth()
{
    std::cout << "pwet";
}

I do not see why it crashes too. Do anyone have any idea?

[Modifier]

Your Base constructor does not make sense. Also when you build Base, Ext is not built yet, and so you have no right to call a method.

[Heather5]

If that is the case then why does it work in debug? Compiling error?

[MindSpace]

I see no reason for it to work in debug at your place. I tested myself your code with VC++ 9 and it crashes indeed in debug (once corrected typos and added a call through, because that base does not compile since you're not supposed to directly call a pure virtual function in constructor).

[Heather5]

In my code actually Base launches a thread that calls doSmth(). I tried simplifying my code and suddenly the compiler sees it.