Why pre-increment operator gives rvalue in C?

Question

In C++, pre-increment operator gives lvalue because incremented object itself is returned, not a copy. But in C, it gives rvalue. Why?

Answer 1

Off the top of my head, I can't imagine any useful statements that could result from using a pre-incremented variable as an lvalue. In C++, due to the existence of operator overloading, I can. Do you have a specific example of something that you're prevented from doing in C, due to this restriction?