Re: Exception handling the right way

From:

"Chris M. Thomasson" <no@spam.invalid>

Newsgroups:

comp.lang.c++

Date:

Tue, 9 Sep 2008 02:03:27 -0700

Message-ID:

<jUqxk.41788$_s1.19525@newsfe07.iad>

"Bart Friederichs" <bf@tbwb.nl> wrote in message
news:48c63859$0$186$e4fe514c@news.xs4all.nl...

anon wrote:

I like this explanation:
http://www.boost.org/community/error_handling.html

Thanks for the pointers, and I started a little experimenting. Soon I
ran into this problem:

int main () {
A *a; B *b; C *c;
try {
    a = new A();
    b = new B();
    c = new C();
   } catch (...) {
     delete a;
     delete b;
     delete c;
   }

return 0;
}

there are some errors here... Simple fix:

int main() {
  A* a = NULL;
  B* b = NULL;
  C* c = NULL;
  try {
    a = new A;
    b = new B;
    c = new C;
  } catch(...) {
    delete a;
    delete b;
    delete c;
  }
  return 0;
}

or, even better:

int main() {
  std::auto_ptr<A> a(new A);
  std::auto_ptr<B> b(new B);
  std::auto_ptr<C> c(new C);
  return 0;
}

Which results in a runtime error when B's contructor throws an
exception. How to correctly free resources on the heap in exception
handling?