[xamuel]

This is a really great example why you SHOULDN'T think of sizeof as a function. If sizeof were a function, the code

  int *foo = NULL;
  foo = malloc(sizeof(*foo));

would be undefined behavior (dereferencing NULL)!

[Kranar]

Dereferencing a null pointer is legal in C. It's the conversion of a null pointer from from an r-value to an l-value that's illegal, which does not happen in that snippet of code.

That's why it's perfectly legal in C to do this (&*foo), even if foo is a null pointer.

[masklinn]

> Dereferencing a null pointer is legal in C. It's the conversion of a null pointer from from an r-value to an l-value that's illegal, which does not happen in that snippet of code.

And it does not happen in that snippet of code because sizeof is nothing like a function.