Re: Exception not unwinding the stack on g++ 4.5.1 ?

Hi,

I've found a very strange behavior in g++ 4.5.1 and would like to know
if I'm missing something obvious.

Given this trivial code :

--------------------
#include<iostream>
#include<stdexcept>

struct A {
   A() { std::cerr<< "A::A()"<< std::endl; std::flush(std::cerr); }
   ~A() { std::cerr<< "A::~A()"<< std::endl; std::flush(std::cerr); }
};

void f() {
   A a;
   throw std::runtime_error("toto");
}

int main() {
   f();
}
--------------------

I expected to see both prints from ctor& dtor on output, though, that
is not what happens.

Output:

--------------------
$ g++ -O0 -fno-inline terminate.cc&& ./a.out
A::A()
terminate called after throwing an instance of 'std::runtime_error'
   what(): toto
Aborted
--------------------

At first I thought that there might be some optimizer magic involved but
even with -O0 -fno-inline the dtor is still not called.

Interestingly enough, adding a try {} catch {} block around the call to
f() solves the problem:

--------------------
#include<iostream>
#include<stdexcept>

struct A {
   A() { std::cerr<< "A::A()"<< std::endl; std::flush(std::cerr); }
   ~A() { std::cerr<< "A::~A()"<< std::endl; std::flush(std::cerr); }
};

void f() {
   A a;
   throw std::runtime_error("toto");
}

int main() {
   try {
     f();
   }
   catch(...) {
     throw;
   }
}
--------------------

Output:

--------------------
$ g++ -O0 -fno-inline terminate.cc&& ./a.out
A::A()
A::~A()
terminate called after throwing an instance of 'std::runtime_error'
   what(): toto
Aborted

Is there something I'm missing here?