String Error

[MoLAoS]

What does it mean if I am calling a function to read a string and it crashes with the debugger just pointing at the function? It doesn't go any farther. However if I put the same function call into throw runtime_error() it outputs the proper contents to the console?

string name = skillTypes[i]->getName();

This gives me an error where the VC++ debugger points to:

string getName() const {return m_name;}

In the class declaration. When I was fiddling I managed to get something where in xstring it told my something about an iterator. But I forget what I did.

throw runtime_error(skillTypes[i]->getName());

The above code causes the console to display the name I would expect to see. Why does it work for runtime_error but not assigning a string?

For reference I used another class that inherits from the one that getName() is from and the getName() called works fine. The constructor constructs the class with m_name set to "default".

I'm sorry if I am missing some info. If I knew any better what to show I could probably have solved it on my own.

[vlad from moscow]

Without seeing your code it is difficult to say what is the problem. I only can guess that it can be related with the index value used in expression skillTypes[i]

[MoLAoS]

That can't be it as I explained. If it was some sort of index error then throwing a runtime_error wouldn't output the correct text. I call that using the same index in the same loop as the line that doesn't work. The first line is directly on top of the other one.

throw runtime_error(skillTypes[i]->getName());
string name = skillTypes[i]->getName();

That is the position of the two lines. The first one puts the proper text into the console. Then I comment it out and the second line throws the error.

    for (int i = 0; i < skillTypes.size(); ++i) {
        m = n->addChild("skill");
        //throw runtime_error(skillTypes[i]->getName());
        const SkillType *skill = skillTypes[i];
        string name = skill->getName();
        m->addAttribute("name", name);
    }

Maybe this will make it clearer. Uncommenting the throw line causes the console output to display the string I want. Otherwise I get the error.

[vlad from moscow]

It is not clear whether pointers stored in skillTypes are valid pointers.

[MoLAoS]

If they weren't valid then how would runtime error output the expected string to the console? If they pointed to the wrong spot I should get some sort of access violation or something.

[vlad from moscow]

In my opinion the program has undefined behavior.

[MoLAoS]

More like I have an undefined level of intelligence. Sometimes I work fine and sometimes I crash and burn.

If its any consolation you did help me. I probably wouldn't have figured it out if I wasn't so sure it wasn't my pointers. Your diagnosis was absolutely right but the problem was in such a different part of the program that I didn't check.

Of course it was the pointers. Turns out I had disabled initMoveSkill for this particular part of the program to focus on other stuff. It would work sometimes, probably if I got the error on the attack skill. It would always crash without the error because it would accept the first skill and crash on the non-existent second one or crash if that was the first one.