sizeof(x)

In C99 it is mentioned:

"The sizeof operator yields the size (in bytes) of its operand, which
may be an expression or the parenthesized name of a type.".


If I am not wrong, this implies that

int x;

size_t y= sizeof(x);


is not valid.


and only the following is valid:


int x;

size_t y= sizeof x;


However I am puzzled, and thought the first was also valid in
C90/C95(/C++03).