8 Expressions [expr]

8.5 Compound expressions [expr.compound]

8.5.2 Unary expressions [expr.unary]

8.5.2.6 Alignof [expr.alignof]

An alignof expression yields the alignment requirement of its operand type.
The operand shall be a type-id representing a complete object type, or an array thereof, or a reference to one of those types.
The result is an integral constant of type std​::​size_­t.
When alignof is applied to a reference type, the result is the alignment of the referenced type.
When alignof is applied to an array type, the result is the alignment of the element type.