SirSmokeALot
asked on
auto_ptr problem :(
Hi out there,
I've got a memory leak here and can't stuff it :(
Here's the stripped down code:
typedef std::vector<std::auto_ptr<
t_LIVector FillVector()
{
t_LIVector v;
auto_ptr<LicenseInfo> LI(new LicenseInfo);
v.push_back(LI);
return v;
}
t_LIVector vLI = FillVector();
The memory allocated for LI is never freed why?
I thoughed the auto_ptr class manages all the clean up.
Tobias
I've got a memory leak here and can't stuff it :(
Here's the stripped down code:
typedef std::vector<std::auto_ptr<
t_LIVector FillVector()
{
t_LIVector v;
auto_ptr<LicenseInfo> LI(new LicenseInfo);
v.push_back(LI);
return v;
}
t_LIVector vLI = FillVector();
The memory allocated for LI is never freed why?
I thoughed the auto_ptr class manages all the clean up.
Tobias
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Can be implemented different. One class of owning objects keeps the counter and the link to the managed object. The visible smart pointer objects stores only one pointer to a shared owner object. The implementation nietod gives uses one less indirection, so it is a very tiny bit faster, but uses more memory; two pointers in each smart pointer object. But that is all rather insignificant.
Actually the method you suggest is more like what I use. I was just trying to keep it simple.
>> have plagued the standards committee for a
>> long time. I'm not sure what the final
>> outcome is.
This weird--I would say nearly useles--form was the final decission. I can't understand why it would have been hotly debated. There is really only one clear choice, and it isn't this one. :-)
But, as kangaroo said, you can write a reference counting autopointer class that will work with any STL container.
Typically the reason one doesn't use reference counting is that the object the pointer points to must store a reference count which means that it has to be a struct/class and it has to have some well-defined properties, which means you cannot use the reference counting pointer with the basic types (char, int...) or with class types that were written without these properties (like from a commercial library). However, it can be done. You simply store the reference count in a 2nd dynmically allocated memory location. So the smart pointer class must maintian two pointer data members. a pointer to the reference count and a pointer to the object that the smart pointer acts like a pointer to.