What is the size of void?

by

The type void has no size; that would be a compilation error. For the same reason you can’t do something like:

void n;

EDIT.
To my surprise, doing sizeof(void) actually does compile in GNU C:

$ echo 'int main() { printf("%d", sizeof(void)); }' | gcc -xc -w - && ./a.out 
1

However, in C++ it does not:

$ echo 'int main() { printf("%d", sizeof(void)); }' | gcc -xc++ -w - && ./a.out 
<stdin>: In function 'int main()':
<stdin>:1: error: invalid application of 'sizeof' to a void type
<stdin>:1: error: 'printf' was not declared in this scope

More Related Contents:

  1. Does not evaluating the expression to which sizeof is applied make it legal to dereference a null or invalid pointer inside sizeof in C++?
  2. When does invoking a member function on a null instance result in undefined behavior?
  3. Optimizing away a “while(1);” in C++0x
  4. Is the sizeof(some pointer) always equal to four?
  5. trap representation
  6. Is `reinterpret_cast`ing between hardware SIMD vector pointer and the corresponding type an undefined behavior?
  7. Is sizeof(bool) defined in the C++ language standard?
  8. Does “Undefined Behavior” really permit *anything* to happen? [duplicate]
  9. Is passing a C++ object into its own constructor legal?
  10. std::ignore with structured bindings?
  11. Why is it not possible to overload class templates?
  12. treating memory returned by operator new(sizeof(T) * N) as an array
  13. Is circumventing a class’ constructor legal or does it result in undefined behaviour?
  14. Static member access in constant expressions
  15. Why is f(i = -1, i = -1) undefined behavior?
  16. Why is the std::initializer_list constructor preferred when using a braced initializer list?
  17. Why does `int ;` compile fine in C, but not in C++?
  18. What happened to the “aggregate or union type that includes one of the aforementioned types” strict aliasing rule?
  19. Can I Reference Previous Members of an Initializer List?
  20. Does this code from “The C++ Programming Language” 4th edition section 36.3.6 have well-defined behavior?
  21. Are int8_t and uint8_t intended to be char types?
  22. Why doesn’t an if constexpr make this core constant expression error disappear?
  23. what is the size of an enum type data in C++?
  24. Use of typename keyword with typedef and new
  25. Lifetime of object is over before destructor is called?
  26. Are pointers to non-static member function “formally” not considered pointers
  27. Why do (only) some compilers use the same address for identical string literals?
  28. Can we apply content not explicitly cited from the normative references to the C++ standard?
  29. Calling delete on NULL pointers – C++03 vs C++11
  30. Is char default-promoted?

Leave a Comment