Currently, the WeakPointerTo comparison operators compare the raw pointers, but this is not useful as it may cause a false equality if one weak pointer in the comparison is expired and points to memory that has since been reused.
Instead, we can define a comparison based on the control block pointer, which exists since the new weak pointer implementation in 0bb81a43c9e4fffb37cc2234c1b0fbae42020ceb. This is implemented in the owner_before method, matching C++11 std::weak_ptr semantics.
I would now recommend deprecating most comparison operators of WeakPointerTo or redefining them to make more sense, ie. comparing equal if they (once) referred to the same object and not if they simply point to the same memory address. This has not yet been done, though code that uses the comparison operators has been fixed in this commit.
Overloads of std::owner_less have been provided for creating a map or set with Weak(Const)PointerTo keys.
These methods are supposed to override the underlying C methods, which do have underscore aliases, so it is important that the Python class defines these underscore aliases as well.
Some drivers would report the wrong internal format. But it's silly that we query the internal format anyway, since buffer textures have a fixed sized internal format.
This is inefficient because it induces an unnecessary ref()/unref() pair when we just need to move the pointer out of the function. Thanks to 23128e4695d2e8581551be161f20cf7d53ca87b5, we can now move between related pointer types, making the .p() hack unnecessary.
This makes it possible to implicitly convert a PT of a derived type to a (C)PT of a base type, without needing to first convert it to a regular pointer. This also applies to moves, which are now more efficient due to the lack of need for ref/unref pair even if the pointer type is not exactly the same.
I'm not sure why they were ifdeffed out, but they should certainly be available so that it is possible to compare WeakPointerTo in a thread-safe manner.
