ceph/src/boost/libs/mpl/doc/src/refmanual/c_str.rst

   1 .. Metafunctions/String Operations//c_str |10
   2
   3
   4 c_str
   5 =====
   6
   7 Synopsis
   8 --------
   9
  10 .. parsed-literal::
  11
  12     template<
  13           typename Sequence
  14         >
  15     struct c_str
  16     {
  17         typedef |unspecified| type;
  18         static char const value[];
  19     };
  20
  21
  22 Description
  23 -----------
  24
  25 ``c_str`` converts the |Forward Sequence| of |Integral Constant|\ s ``Sequence``
  26 into a null-terminated byte string containing an equivalent sequence.
  27
  28
  29 Header
  30 ------
  31
  32 .. parsed-literal::
  33
  34     #include <boost/mpl/string.hpp>
  35
  36
  37 Model of
  38 --------
  39
  40 |Metafunction|
  41
  42
  43 Parameters
  44 ----------
  45
  46 +---------------+---------------------------+-----------------------------------------------+
  47 | Parameter     | Requirement               | Description                                   |
  48 +===============+===========================+===============================================+
  49 | ``Sequence``  | |Forward Sequence| of     | A sequence to be converted into a             |
  50 |               | |Integral Constant|\ s    | null-terminated byte string.                  |
  51 +---------------+---------------------------+-----------------------------------------------+
  52
  53
  54 Expression semantics
  55 --------------------
  56
  57 .. compound::
  58     :class: expression-semantics
  59
  60     For any |Forward Sequence| of |Integral Constant|\ s ``s``,
  61
  62     .. parsed-literal::
  63
  64         c_str<s>::value;
  65
  66     :Return type:
  67         A null-terminated byte string.
  68
  69     :Precondition:
  70         ``size<s>::value <= BOOST_MPL_STRING_MAX_LENGTH``.
  71
  72     :Semantics:
  73         Equivalent to
  74
  75         .. parsed-literal::
  76
  77            char const value[] = {
  78                at<s, 0>::type::value
  79              , ...
  80              , at<s, size<s>::value-1>::type::value
  81              , '\\0'
  82            };
  83
  84 Complexity
  85 ----------
  86
  87 +-------------------------------+-----------------------------------+
  88 | Sequence archetype            | Complexity                        |
  89 +===============================+===================================+
  90 | |Forward Sequence|            | Linear.                           |
  91 +-------------------------------+-----------------------------------+
  92
  93 Example
  94 -------
  95
  96 .. parsed-literal::
  97
  98     typedef vector_c<char,'h','e','l','l','o'> hello;
  99     assert( 0 == std::strcmp( c_str<hello>::value, "hello" ) );
 100
 101 See also
 102 --------
 103
 104 |Forward Sequence|, |Integral Constant|, |string|
 105
 106
 107 .. copyright:: Copyright ©  2009 Eric Niebler
 108    Distributed under the Boost Software License, Version 1.0. (See accompanying
 109    file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)