I believe that the C standard now explicitly supports casting a struct to the type of its first member. I learned the pattern in the late 90s from looking at th

I believe that the C standard now explicitly supports casting a struct to the type of its first member. I learned the pattern in the late 90s from looking at the gtk project's glib library. Then I realized I sometimes needed to downcast, so the base struct ended up with a type enum. And then I realized sometimes I wanted to call specialized functions, so I reinvented vtables. To this day I consider C++ an unwieldy over-complicated beast with a specification that is literally too complex for a verifiable implementation, but that brief exercise gave me a sufficient appreciation for the designers of C++ to respect their creation.