tmp/tmpb4wm13tx/{from.md → to.md}
RENAMED
|
@@ -0,0 +1,14 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
### Hash support <a id="optional.hash">[[optional.hash]]</a>
|
| 2 |
+
|
| 3 |
+
``` cpp
|
| 4 |
+
template <class T> struct hash<optional<T>>;
|
| 5 |
+
```
|
| 6 |
+
|
| 7 |
+
The specialization `hash<optional<T>>` is enabled ([[unord.hash]]) if
|
| 8 |
+
and only if `hash<remove_const_t<T>>` is enabled. When enabled, for an
|
| 9 |
+
object `o` of type `optional<T>`, if `bool(o) == true`, then
|
| 10 |
+
`hash<optional<T>>()(o)` shall evaluate to the same value as
|
| 11 |
+
`hash<remove_const_t<T>>()(*o)`; otherwise it evaluates to an
|
| 12 |
+
unspecified value. The member functions are not guaranteed to be
|
| 13 |
+
`noexcept`.
|
| 14 |
+
|