Why this broken c++ code works?

Question

I'm testing some flascc code, and I'm trying to trow some errors, but it seems that my tests just return NULL or zero, and never stop the execution, and I think this is not desired.
For example:
Error *errorClass = NULL;
int myVar = errorClass->foo();
I think this should trow an error while calling a function of a NULL pointer but it's not the case.
Also, I've tried some divisions by zero, and there is no error, just returns 0

Answer 1

This doesn't have to crash unless you try to access the attribute of your Error object in Error::foo().
This is not against the c++98 standard (haven't verified), but this code will also run on vanilla gcc.
Method code are almost like normal function, but they are given the object as a "this" parameter so it can works on its attributes.
So let's say that in Error::foo() you do this : printf("hello world)
What your code do is the equivalent of
     void foo(Error * this){
          std::cout << "hello world" std::endl;
     int main(){
          foo(NULL);
          return 0;
This code won't crash, but as soon you try to access the attribute this is another story. So, it really depend on what you do in Error::foo().
For the zero division, the standard left this as an undefined behavior. So it's perfectly normal, on some compiler/architecture it will crash, on others not. It's left to the compiler implementation as to what should happen.
So nothing in what you say should cause the program to crash, it might, but it might not, it isn't a bug, it's just undefined in the standard.
You should manually check for error, C++ is way more low level than AS3 it won't stop you from shooting yourself in the foot, but that's also one of the reason why it is so flexible and performant.