[fauigerzigerk]

It's the ownership problem that makes garbage collection useful. Tracking who owns which piece of memory at a particular point in time is a lot of work. Every API has to document if and how an object returned as a pointer should be freed and if an incoming pointer continues to be owned by the caller or not. Every single library invents its very own memory management pattern and you have to keep them all in your head or bad things will happen.

Look at libpq for instance. There are several functions that free memory and destroy different types of objects: PQclear, PQfreemem, PQfinish, PQconninfoFree and maybe others that I forget. For some API functions the documentation explicitly states which free function to use, for others it says nothing and for yet others it says not to free anything because another object retains ownership.

C++ tries to solve the problem that libpq has by using RAII and destructors, but it opened a can of worms. Now you have to deal with tons of different types of smart pointers and fancy memory management patterns coming from different libraries and frameworks. And you must never think that smart pointers are really pointers because if you do, bad things will happen:

Can you return the this pointer from a member function? Not if someone else holds a shared_ptr to this. Can you return shared_ptr<ThisClass>(this)? No, because now you may have two different reference counts for the same object. Can you return shared_from_this() after inheriting enable_shared_from_this? Only if at least one shared_ptr already points at this, which depends on how the caller created this. Is SomeClassPtr a SomeClass*, a shared_ptr<SomeClass> or maybe a boost::intrusive_ptr<SomeClass>? Go find the typedef.

So garbage collection is desirable. Unfortunately it seems to be a very difficult problem to solve in the face of large amounts of memory and lots of parallelism, which is exactly where we're headed. I wish Oracle would buy Azul and make their garbage collector available in OpenJDK. The world would be a better place and I would forgive them all the nasty stuff they have done recently :)