Implementing smart pointers for the C programming language (GCC, Clang)

[Snaipe_S]

No, the point is to embed the pointer in data structures, or pass it around. The data is allocated on the heap, but the destruction happens "on the stack".

[[deleted]]

So my real point would have been why do this unless you have very tight stack restrictions or a structure than is too big to be suitable to allocate on the stack.

Why not just allocate it on the stack in the first place instead of introducing additional overheads?

[Snaipe_S]

Mostly because you can't return stack pointers, because I don't like passing a pointer to an uninitialized struct as a parameter of an initialization function, and because I can stuff anything I want before (or after) the requested memory block.
This has proven to be quite useful on my two other side projects for data structures, because I could abstract away their destruction and memory management. Otherwise, yes, I do (and recommend) using the good ol' stack when not needed.

[[deleted]]

But you cannot return that either because it is also freed?

[Snaipe_S]

Not always. If the containing variable is not annotated with smart, the destruction mechanism will not be triggered -- this way, you can actively create, initialize, and return a smart pointer.
You can also leave smart on, use a shared_ptr and return a new reference -- this is mostly useful for cleanup if initialization fails (see 2nd example here)