Why does an enum require extra memory size?

by

In Rust, unlike in C, enums are tagged unions. That is, the enum knows which value it holds. So 8 bytes wouldn’t be enough because there would be no room for the tag.

More Related Contents:

  1. Why is a trait not implemented for a type that clearly has it implemented?
  2. How can I include a module from another file from the same project?
  3. What does “Sized is not implemented” mean?
  4. Deriving a trait results in unexpected compiler error, but the manual implementation works
  5. How do I implement Copy and Clone for a type that contains a String (or any type that doesn’t implement Copy)?
  6. Mutably borrow one struct field while borrowing another in a closure
  7. What makes something a “trait object”?
  8. Change enum variant while moving the field to the new variant
  9. When is it useful to define multiple lifetimes in a struct?
  10. Can I write an Iterator that mutates itself and then yields a reference into itself?
  11. How to update-or-insert on a Vec?
  12. How do I include the end value in a range?
  13. How do I specify lifetime parameters in an associated type?
  14. How do I invoke a system command and capture its output?
  15. How to return a string (or similar) from Rust in WebAssembly?
  16. Can I destructure a tuple without binding the result to a new variable in a let/match/for statement?
  17. What is the difference between Copy and Clone?
  18. Is it possible to have stack allocated arrays with the size determined at runtime in Rust?
  19. How to format output to a byte array with no_std and no allocator?
  20. What is the right way to allocate data to pass to an FFI call?
  21. How can I distinguish between a deserialized field that is missing and one that is null?
  22. Cannot create a generic function that uses a literal zero
  23. Is there a way to combine multiple traits in order to define a new trait? [duplicate]
  24. How to avoid temporary allocations when using a complex key for a HashMap?
  25. Why does compilation not fail when a member of a moved value is assigned to?
  26. What does “missing lifetime specifier” mean when storing a &str in a structure?
  27. What is the purpose of the unit type in Rust?
  28. Why does the Rust compiler request I constrain a generic type parameter’s lifetime (error E0309)?
  29. Cannot pass self as callback parameter due to double borrowing
  30. How do I create a HashMap with type erased keys?

Leave a Comment