Type of comparisons and conditionals

[Victor Bazarov]

[ ... ]

Right. I thought it's also OK to subtract two pointers if they
point to objects which are subobjects of the same object, but I just
checked and didn't find that. Strange.

$5.7/6: "Unless both pointers point to elements of the same array
object, or one past the last element of the array object, the
behavior is undefined."

Yes, and?

 

[Jerry Coffin]

[ ... ]

Right. I thought it's also OK to subtract two pointers if they
point to objects which are subobjects of the same object, but I just
checked and didn't find that. Strange.

$5.7/6: "Unless both pointers point to elements of the same array
object, or one past the last element of the array object, the
behavior is undefined."

Yes, and?

And therefore, if they are subobjects of the same object (rather than
elements of the same array) the behavior is undefined.