ceph/src/boost/libs/type_traits/doc/extent.qbk

   1 [/
   2   Copyright 2007 John Maddock.
   3   Distributed under the Boost Software License, Version 1.0.
   4   (See accompanying file LICENSE_1_0.txt or copy at
   5   http://www.boost.org/LICENSE_1_0.txt).
   6 ]
   7
   8 [section:extent extent]
   9    template <class T, std::size_t N = 0>
  10    struct extent : public __integral_constant<std::size_t, EXTENT(T,N)> {};
  11
  12 __inherit Class template extent inherits from `__integral_constant<std::size_t, EXTENT(T,N)>`,
  13 where `EXTENT(T,N)` is the number of elements in the N'th array dimension of type `T`.
  14
  15 If `T` is not a (built-in) array type, or if `N > __rank<T>::value`, or if the N'th array bound
  16 is incomplete, then `EXTENT(T,N)` is zero.
  17
  18 __header ` #include <boost/type_traits/extent.hpp>` or ` #include <boost/type_traits.hpp>`
  19
  20 __examples
  21
  22 [:`extent<int[1]>` inherits from `__integral_constant<std::size_t, 1>`.]
  23
  24 [:`extent<double[2][3][4], 0>::type` is the type `__integral_constant<std::size_t, 2>`.]
  25
  26 [:`extent<double[2][3][4], 1>::type` is the type `__integral_constant<std::size_t, 3>`.]
  27
  28 [:`extent<double[2][3][4], 2>::type` is the type `__integral_constant<std::size_t, 4>`.]
  29
  30 [:`extent<int[4]>::value` is an integral constant
  31 expression that evaluates to /4/.]
  32
  33 [:`extent<int[][2]>::value` is an integral constant
  34 expression that evaluates to /0/.]
  35
  36 [:`extent<int[][2], 1>::value` is an integral constant
  37 expression that evaluates to /2/.]
  38
  39 [:`extent<int*>::value` is an integral constant
  40 expression that evaluates to /0/.]
  41
  42 [:`extent<boost::array<int, 3> >::value` is an integral constant
  43 expression that evaluates to /0/: `boost::array` is a class type and [*not an array type]!]
  44
  45 [:`extent<T>::value_type` is the type `std::size_t`.]
  46
  47 [all_compilers]
  48
  49 [endsect]
  50