projects / ceph.git / blame
| Commit | Line | Data |
|---|---|---|
| 7c673cae FG |
1 | .. Data Types/Miscellaneous//void_ |100 |
| 2 | ||
| 3 | void\_ | |
| 4 | ====== | |
| 5 | ||
| 6 | Synopsis | |
| 7 | -------- | |
| 8 | ||
| 9 | .. parsed-literal:: | |
| 10 | ||
| 11 | struct void\_ | |
| 12 | { | |
| 13 | typedef void\_ type; | |
| 14 | }; | |
| 15 | ||
| 16 | template< typename T > struct is_void; | |
| 17 | ||
| 18 | ||
| 19 | Description | |
| 20 | ----------- | |
| 21 | ||
| 22 | ``void_`` is a generic type placeholder representing "nothing". | |
| 23 | ||
| 24 | .. In many cases, returning ``void_`` from a metafunction to signal | |
| 25 | an absence of the requested data leads to a simpler user code than | |
| 26 | having a separate metafunction specifically for the purpose of | |
| 27 | performing the corresponding check. | |
| 28 | ||
| 29 | Header | |
| 30 | ------ | |
| 31 | ||
| 32 | .. parsed-literal:: | |
| 33 | ||
| 34 | #include <boost/mpl/void.hpp> | |
| 35 | ||
| 36 | ||
| 37 | See also | |
| 38 | -------- | |
| 39 | ||
| 40 | |Data Types|, |pair|, |empty_base|, |bool_|, |int_|, |integral_c| | |
| 41 | ||
| 42 | ||
| 43 |