Re: [Boost-users] Accessing members from a shared pointer passed as argument to a function gives incorrect results without typecast

15 Apr 2013

      On 4/15/2013 6:02 AM, Deepak Gunjal wrote:
...
Hi,
class A;
class B;
typedef boost::shared_ptr<A> pSharedPtrA;
typedef boost::shared_ptr<B> pSharedPtrB;
class B   {
public:
int memberB;
};
Class A   {
public:
pSharedPtrB pMember;
};
Suppose i have one shared pointer of type pSharedPtrA pointing to an
object of class A and the member variable pMember pinging to a valid
object of class B.
Now if i pass the shared pointer of type pSharedPtrA to a function
suppose Test_Func(pSharedPtrA):
void Test_Func(pSharedPtrA  pLocalA)
{
  pSharedPtrA ptrA =  boost::static_pointer_cast<A> (pLocalA)
pSharedPtrB tmpB = boost::static_pointer_cast<B>(ptrA->pMember)
Another_Func(tmpB)
}
Another_Func(pSharedPtrB pLocalB)
{
    int x = pLocalB->memberB; //Gives WRONG value
   pSharedPtrB   ptmp = boost::static_pointer_cast<B> (pLocalB)
   x = ptmp ->memberB; //Gives CORRECT Value
}
The problem is when typecast is not used then in function
Another_Func(pSharedPtrB pLocalB), pLocalB->memberB is not giving the
correct result but after typecast it is giving the correct results.
In the code above memberB is never initialized, so how do you know what 
is the correct value?

Provide a minimal fully compiling, runnable example. Doing so will 
probably uncover your problem, and at least will allow others to run 
your example.

Jeff

Re: [Boost-users] Accessing members from a shared pointer passed as argument to a function gives incorrect results without typecast

Jeff Flinn