TimeTraits.html 9.2 KB

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  19. <div class="titlepage"><div><div><h3 class="title">
  20. <a name="asio.reference.TimeTraits"></a><a class="link" href="TimeTraits.html" title="Time traits requirements">Time traits requirements</a>
  21. </h3></div></div></div>
  22. <p>
  23. In the table below, <code class="computeroutput"><span class="identifier">X</span></code> denotes
  24. a time traits class for time type <code class="computeroutput"><span class="identifier">Time</span></code>,
  25. <code class="computeroutput"><span class="identifier">t</span></code>, <code class="computeroutput"><span class="identifier">t1</span></code>,
  26. and <code class="computeroutput"><span class="identifier">t2</span></code> denote values of type
  27. <code class="computeroutput"><span class="identifier">Time</span></code>, and <code class="computeroutput"><span class="identifier">d</span></code>
  28. denotes a value of type <code class="computeroutput"><span class="identifier">X</span><span class="special">::</span><span class="identifier">duration_type</span></code>.
  29. </p>
  30. <div class="table">
  31. <a name="asio.reference.TimeTraits.t0"></a><p class="title"><b>Table&#160;38.&#160;TimeTraits requirements</b></p>
  32. <div class="table-contents"><table class="table" summary="TimeTraits requirements">
  33. <colgroup>
  34. <col>
  35. <col>
  36. <col>
  37. </colgroup>
  38. <thead><tr>
  39. <th>
  40. <p>
  41. expression
  42. </p>
  43. </th>
  44. <th>
  45. <p>
  46. return type
  47. </p>
  48. </th>
  49. <th>
  50. <p>
  51. assertion/note<br> pre/post-condition
  52. </p>
  53. </th>
  54. </tr></thead>
  55. <tbody>
  56. <tr>
  57. <td>
  58. <p>
  59. <code class="computeroutput"><span class="identifier">X</span><span class="special">::</span><span class="identifier">time_type</span></code>
  60. </p>
  61. </td>
  62. <td>
  63. <p>
  64. <code class="computeroutput"><span class="identifier">Time</span></code>
  65. </p>
  66. </td>
  67. <td>
  68. <p>
  69. Represents an absolute time. Must support default construction,
  70. and meet the requirements for <code class="computeroutput"><span class="identifier">CopyConstructible</span></code>
  71. and <code class="computeroutput"><span class="identifier">Assignable</span></code>.
  72. </p>
  73. </td>
  74. </tr>
  75. <tr>
  76. <td>
  77. <p>
  78. <code class="computeroutput"><span class="identifier">X</span><span class="special">::</span><span class="identifier">duration_type</span></code>
  79. </p>
  80. </td>
  81. <td>
  82. </td>
  83. <td>
  84. <p>
  85. Represents the difference between two absolute times. Must support
  86. default construction, and meet the requirements for <code class="computeroutput"><span class="identifier">CopyConstructible</span></code> and <code class="computeroutput"><span class="identifier">Assignable</span></code>. A duration can be
  87. positive, negative, or zero.
  88. </p>
  89. </td>
  90. </tr>
  91. <tr>
  92. <td>
  93. <p>
  94. <code class="computeroutput"><span class="identifier">X</span><span class="special">::</span><span class="identifier">now</span><span class="special">();</span></code>
  95. </p>
  96. </td>
  97. <td>
  98. <p>
  99. <code class="computeroutput"><span class="identifier">time_type</span></code>
  100. </p>
  101. </td>
  102. <td>
  103. <p>
  104. Returns the current time.
  105. </p>
  106. </td>
  107. </tr>
  108. <tr>
  109. <td>
  110. <p>
  111. <code class="computeroutput"><span class="identifier">X</span><span class="special">::</span><span class="identifier">add</span><span class="special">(</span><span class="identifier">t</span><span class="special">,</span>
  112. <span class="identifier">d</span><span class="special">);</span></code>
  113. </p>
  114. </td>
  115. <td>
  116. <p>
  117. <code class="computeroutput"><span class="identifier">time_type</span></code>
  118. </p>
  119. </td>
  120. <td>
  121. <p>
  122. Returns a new absolute time resulting from adding the duration
  123. <code class="computeroutput"><span class="identifier">d</span></code> to the absolute
  124. time <code class="computeroutput"><span class="identifier">t</span></code>.
  125. </p>
  126. </td>
  127. </tr>
  128. <tr>
  129. <td>
  130. <p>
  131. <code class="computeroutput"><span class="identifier">X</span><span class="special">::</span><span class="identifier">subtract</span><span class="special">(</span><span class="identifier">t1</span><span class="special">,</span>
  132. <span class="identifier">t2</span><span class="special">);</span></code>
  133. </p>
  134. </td>
  135. <td>
  136. <p>
  137. <code class="computeroutput"><span class="identifier">duration_type</span></code>
  138. </p>
  139. </td>
  140. <td>
  141. <p>
  142. Returns the duration resulting from subtracting <code class="computeroutput"><span class="identifier">t2</span></code>
  143. from <code class="computeroutput"><span class="identifier">t1</span></code>.
  144. </p>
  145. </td>
  146. </tr>
  147. <tr>
  148. <td>
  149. <p>
  150. <code class="computeroutput"><span class="identifier">X</span><span class="special">::</span><span class="identifier">less_than</span><span class="special">(</span><span class="identifier">t1</span><span class="special">,</span>
  151. <span class="identifier">t2</span><span class="special">);</span></code>
  152. </p>
  153. </td>
  154. <td>
  155. <p>
  156. <code class="computeroutput"><span class="keyword">bool</span></code>
  157. </p>
  158. </td>
  159. <td>
  160. <p>
  161. Returns whether <code class="computeroutput"><span class="identifier">t1</span></code>
  162. is to be treated as less than <code class="computeroutput"><span class="identifier">t2</span></code>.
  163. </p>
  164. </td>
  165. </tr>
  166. <tr>
  167. <td>
  168. <p>
  169. <code class="computeroutput"><span class="identifier">X</span><span class="special">::</span><span class="identifier">to_posix_duration</span><span class="special">(</span><span class="identifier">d</span><span class="special">);</span></code>
  170. </p>
  171. </td>
  172. <td>
  173. <p>
  174. <code class="computeroutput"><span class="identifier">date_time</span><span class="special">::</span><span class="identifier">time_duration_type</span></code>
  175. </p>
  176. </td>
  177. <td>
  178. <p>
  179. Returns the <code class="computeroutput"><span class="identifier">date_time</span><span class="special">::</span><span class="identifier">time_duration_type</span></code>
  180. value that most closely represents the duration <code class="computeroutput"><span class="identifier">d</span></code>.
  181. </p>
  182. </td>
  183. </tr>
  184. </tbody>
  185. </table></div>
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  191. <td align="right"><div class="copyright-footer">Copyright &#169; 2003-2014 Christopher M. Kohlhoff<p>
  192. Distributed under the Boost Software License, Version 1.0. (See accompanying
  193. file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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