T belongs to the set of value types of X if, for an object t of type T, *x = t; is well-defined and does not require performing any non-trivial conversions on t. [1]
An Output Iterator may be singular, meaning that the results of most operations, including copying and dereference assignment, are undefined. The only operation that is guaranteed to be supported is assigning a nonsingular iterator to a singular iterator.
An Output Iterator may be dereferenceable, meaning that assignment through it is defined. Dereferenceable iterators are always nonsingular, but nonsingular iterators are not necessarily dereferenceable.
Valid expressions | Name | Expression | Type requirements | Return type |
| Default constructor | X x; X() | | |
| Copy constructor | X(x) | | X |
| Copy constructor | X y(x); or X y = x; | | |
| Dereference assignment | *x = t | t is convertible to a type in the set of value types of X. [1] | Result is not used |
| Preincrement | ++x | | X& |
| Postincrement | (void) x++ | | void |
| Postincrement and assign | *x++ = t; | | Result is not used |
Expression semantics | Name | Expression | Precondition | Semantics | Postcondition |
| Default constructor | X x; X() | | | x may be singular |
| Copy constructor | X(x) | x is nonsingular | | *X(x) = t is equivalent to *x = t [2] |
| Copy constructor | X x(y); or X x = y; | y is nonsingular | | *y = t is equivalent to *x = t [2] |
| Dereference assignment | *x = t | x is dereferenceable. If there has been a previous assignment through x, then there has been an intervening increment. [3] |
