Back to Basics: Class Layout - Stephen Dewhurst - CppCon 2020

[@norikazuoshiro6324]

I learn something new and useful everytime i watch a cppcon video, especially Back to Basics series. Thank you, Mr Stephen Dewhurst for the great talk.

[@georganatoly6646]

hate to admit but I was completely ignorant to , turned out to be an exceptionally informative talk!

[@lck5217]

ДОВЕРЯЙ НО ПРОВЕРЯЙ! GREAT TALK!

[@QuintinMassey]

Proposed augmentation to the statemen that C++ is getting easier to write: it is getting easier to write more complex C++ cause I still don't understand most of it haha. After this presentation, I learned that I know even less about C++ than before. Great presentation! Thank you.

[@YourCRTube]

Imagine a newcomer watching this thinking it's "the basics" 😁 Good talk otherwise, though the second part has a strong overlap with last year talk about virtual classes

[@shmekelfreckles8157]

Do they actually have “the basics”?

[@yjc149]

this is an extremly good talk. thanks Stephen!

[@rodion988]

Thank you Stephen for this lecture, very informative.

[@CppCon]

Glad it was helpful!

[@martinelzen5127]

This was a cool lecture, I'm glad I watched it and learned some things. The explanation of *why* the using-memcmp-across-data-members is a bad thing, could have been clearer, though. If memory serves the standard does *NOT* allow memory to be touched which hasn't been explicitly initialized, which means if any padding gets added anywhere, you've instantly gone to UB-land...

[@poppmeow7586]

it's like going through the book object model within 1 hour. Lots of details to revisit and recap later.

[@QaytbayALAtheer]

What is object/type level protection mentioned @ 6:20 ?!

[@Radioguy00]

Learned a lot of new things. Very clearly explained. Thanks

[@xealit]

C++ is indeed terrific to program embedded systems. It just feels like you talk foreign language to those systems. But if you bend and shoehorn it with templates and meta-programming, it is indeed great. Is there a compiler directive to check that a class is standard layout type? I.e. something like override that checks a member does indeed override something. -- ok, use is_standard_layout_v and many static_asserts. Another example how C++ is just foreign to digital hardware.

[@zzzXopHeTzzz]

A lot of useful information. Thanks!

[@CppCon]

Glad it was helpful! Thank you.

[@KX36]

After watching this I'm amazed upcasting and downcasting works at all...

[@peterevans6752]

Enjoyed the virtual and vtbl discussions in this talk. I'm uncertain I would call it "basics" but more label it "essentials" for class layout. Just because inheritance and multiple inheritance doesn't seem basic at all.

[@konstantinburlachenko2843]

It is all also relative to c++1998, and I think people who worked with c++ for 3-4 years and read book on the subject. Still it is a nice talk to highlight possible problems, even they are pretty old. To learn layouts for compilers sometimes authors of compilers share technical docs.

[@hanyanglee9018]

Maybe the virtual table is not a good design right from the beginning. Multiple inheritance brings whole lot of mess. If we have some meta programming mechanism in c++, while allow us to copy functions into another class, replace and remove some of them, it should be easier. Then the mess is thrown to how a container stores multiple types, or at least pointers of different types while all the pointers are of the same size.

[@riderwang9770]

Stephen is always the best

[@tourdesource]

I was despairing about having to memorize what constitutes a standard layout class. Deeply grateful for std::is_standard_layout. Does it always work?

[@ggodool]

Great talk!

[@alek282]

I guess embedded people are right not to trust C++ after all Great explanations however