Re: [boost] [Review.Coroutine] Lifetime of coroutine parameters

Subject: Re: [boost] [Review.Coroutine] Lifetime of coroutine parameters
From: Oliver Kowalke (oliver.kowalke_at_[hidden])
Date: 2012-09-11 02:46:57

> Surprisingly (well not really), the following example doesn't fails at 
> *1*. This is because the coroutine have access to its coroutine 
> parameters  *2*,  which has a sens only for the first time the coroutine 
> is called.

your exchange addresses between main() and coroutine-fn (lifetime()).
you could use it also a second time etc. as long as the object does not go out of scope.

> Once the first call to yield return, the memory these 
> parameter *3* can point to trash, as the example shows.

sorry - that is not an issue of boost.coroutine itself.

Who would store pointers/references to objects and expects that those objects can still be accessed over the pointers/references after those objects were destroyed. But that is the case in your example.

Your example in issue *3* is equivalent to storing an reference as member in some class and access the member after the original object was gone out of scope.

struct X
{ void g() {} };

struct Y
{
   X  & x;
   Y( X & x_) : x( x_) {}
   void f() { x.g(); }
};

Y u()
{
   X x;
   Y y( x);
   y.f(); // OK
}

void main()
{
  Y y( u() );
  y.f(); // segfault
}

Oliver