projects / ceph.git / blame
| Commit | Line | Data |
|---|---|---|
| 7c673cae FG |
1 | .. Sequences/Intrinsic Metafunctions//clear |
| 2 | ||
| 3 | clear | |
| 4 | ===== | |
| 5 | ||
| 6 | Synopsis | |
| 7 | -------- | |
| 8 | ||
| 9 | .. parsed-literal:: | |
| 10 | ||
| 11 | template< | |
| 12 | typename Sequence | |
| 13 | > | |
| 14 | struct clear | |
| 15 | { | |
| 16 | typedef |unspecified| type; | |
| 17 | }; | |
| 18 | ||
| 19 | ||
| 20 | ||
| 21 | Description | |
| 22 | ----------- | |
| 23 | ||
| 24 | Returns an empty sequence |concept-identical| to ``Sequence``. | |
| 25 | ||
| 26 | ||
| 27 | Header | |
| 28 | ------ | |
| 29 | ||
| 30 | .. parsed-literal:: | |
| 31 | ||
| 32 | #include <boost/mpl/clear.hpp> | |
| 33 | ||
| 34 | ||
| 35 | Model of | |
| 36 | -------- | |
| 37 | ||
| 38 | |Tag Dispatched Metafunction| | |
| 39 | ||
| 40 | ||
| 41 | Parameters | |
| 42 | ---------- | |
| 43 | ||
| 44 | +---------------+-----------------------------------+---------------------------------------+ | |
| 45 | | Parameter | Requirement | Description | | |
| 46 | +===============+===================================+=======================================+ | |
| 47 | | ``Sequence`` | |Extensible Sequence| or | A sequence to get an empty "copy" of. | | |
| 48 | | | |Extensible Associative Sequence| | | | |
| 49 | +---------------+-----------------------------------+---------------------------------------+ | |
| 50 | ||
| 51 | ||
| 52 | Expression semantics | |
| 53 | -------------------- | |
| 54 | ||
| 55 | For any |Extensible Sequence| or |Extensible Associative Sequence| ``s``: | |
| 56 | ||
| 57 | ||
| 58 | .. parsed-literal:: | |
| 59 | ||
| 60 | typedef clear<s>::type t; | |
| 61 | ||
| 62 | :Return type: | |
| 63 | |Extensible Sequence| or |Extensible Associative Sequence|. | |
| 64 | ||
| 65 | :Semantics: | |
| 66 | Equivalent to | |
| 67 | ||
| 68 | .. parsed-literal:: | |
| 69 | ||
| 70 | typedef erase< s, begin<s>::type, end<s>::type >::type t; | |
| 71 | ||
| 72 | ||
| 73 | :Postcondition: | |
| 74 | ``empty<s>::value == true``. | |
| 75 | ||
| 76 | ||
| 77 | Complexity | |
| 78 | ---------- | |
| 79 | ||
| 80 | Amortized constant time. | |
| 81 | ||
| 82 | ||
| 83 | Example | |
| 84 | ------- | |
| 85 | ||
| 86 | .. parsed-literal:: | |
| 87 | ||
| 88 | typedef vector_c<int,1,3,5,7,9,11> odds; | |
| 89 | typedef clear<odds>::type nothing; | |
| 90 | ||
| 91 | BOOST_MPL_ASSERT(( empty<nothing> )); | |
| 92 | ||
| 93 | ||
| 94 | See also | |
| 95 | -------- | |
| 96 | ||
| 97 | |Extensible Sequence|, |Extensible Associative Sequence|, |erase|, |empty|, |begin|, |end| | |
| 98 | ||
| 99 | ||
| 100 |