contents/reference/lttng-modules/lttng-modules-tp-struct-entry.md

   1 ---
   2 id: lttng-modules-tp-struct-entry
   3 ---
   4
   5 This table describes possible entries for the `TP_STRUCT__entry()` part
   6 of `LTTNG_TRACEPOINT_EVENT()`:
   7
   8 <table class="func-desc">
   9     <thead>
  10         <tr>
  11             <th>Macro</th>
  12             <th>Description/arguments</th>
  13         </tr>
  14     </thead>
  15     <tbody>
  16         <tr>
  17             <td>
  18                 <ul>
  19                     <li><code class="no-bg">__field(<span class="arg">t</span>, <span class="arg">n</span>)</code></li>
  20                 </ul>
  21             </td>
  22             <td>
  23                 <p>Standard integer, displayed in base&nbsp;10</p>
  24                 <ul>
  25                     <li>
  26                         <code class="arg">t</code> integer C type
  27                         (<code>int</code>, <code>unsigned char</code>,
  28                         <code>size_t</code>, etc.)
  29                     </li>
  30                     <li><code class="arg">n</code> field name</li>
  31                 </ul>
  32             </td>
  33         </tr>
  34         <tr>
  35             <td>
  36                 <ul>
  37                     <li><code class="no-bg">__field_hex(<span class="arg">t</span>, <span class="arg">n</span>)</code></li>
  38                 </ul>
  39             </td>
  40             <td>
  41                 <p>Standard integer, displayed in base&nbsp;16</p>
  42                 <ul>
  43                     <li><code class="arg">t</code> integer C type</li>
  44                     <li><code class="arg">n</code> field name</li>
  45                 </ul>
  46             </td>
  47         </tr>
  48         <tr>
  49             <td>
  50                 <ul>
  51                     <li><code class="no-bg">__field_oct(<span class="arg">t</span>, <span class="arg">n</span>)</code></li>
  52                 </ul>
  53             </td>
  54             <td>
  55                 <p>Standard integer, displayed in base&nbsp;8</p>
  56                 <ul>
  57                     <li>
  58                         <code class="arg">t</code> integer C type
  59                     </li>
  60                     <li><code class="arg">n</code> field name</li>
  61                 </ul>
  62             </td>
  63         </tr>
  64         <tr>
  65             <td>
  66                 <ul>
  67                     <li><code class="no-bg">__field_network(<span class="arg">t</span>, <span class="arg">n</span>)</code></li>
  68                 </ul>
  69             </td>
  70             <td>
  71                 <p>
  72                     Integer in network byte order (big endian),
  73                     displayed in base&nbsp;10
  74                 </p>
  75                 <ul>
  76                     <li>
  77                         <code class="arg">t</code> integer C type
  78                     </li>
  79                     <li><code class="arg">n</code> field name</li>
  80                 </ul>
  81             </td>
  82         </tr>
  83         <tr>
  84             <td>
  85                 <ul>
  86                     <li><code class="no-bg">__field_network_hex(<span class="arg">t</span>, <span class="arg">n</span>)</code></li>
  87                 </ul>
  88             </td>
  89             <td>
  90                 <p>
  91                     Integer in network byte order (big endian),
  92                     displayed in base&nbsp;16
  93                 </p>
  94                 <ul>
  95                     <li>
  96                         <code class="arg">t</code> integer C type
  97                     </li>
  98                     <li><code class="arg">n</code> field name</li>
  99                 </ul>
 100             </td>
 101         </tr>
 102         <tr>
 103             <td>
 104                 <ul>
 105                     <li><code class="no-bg">__array(<span class="arg">t</span>, <span class="arg">n</span>, <span class="arg">s</span>)</code></li>
 106                 </ul>
 107             </td>
 108             <td>
 109                 <p>Statically-sized array, elements displayed in base&nbsp;10</p>
 110                 <ul>
 111                     <li>
 112                         <code class="arg">t</code> array element C type
 113                     </li>
 114                     <li><code class="arg">n</code> field name</li>
 115                     <li><code class="arg">s</code> number of elements</li>
 116                 </ul>
 117             </td>
 118         </tr>
 119         <tr>
 120             <td>
 121                 <ul>
 122                     <li><code class="no-bg">__array_hex(<span class="arg">t</span>, <span class="arg">n</span>, <span class="arg">s</span>)</code></li>
 123                 </ul>
 124             </td>
 125             <td>
 126                 <p>Statically-sized array, elements displayed in base&nbsp;16</p>
 127                 <ul>
 128                     <li>
 129                         <code class="arg">t</code> array element C type
 130                     </li>
 131                     <li><code class="arg">n</code> field name</li>
 132                     <li><code class="arg">s</code> number of elements</li>
 133                 </ul>
 134             </td>
 135         </tr>
 136         <tr>
 137             <td>
 138                 <ul>
 139                     <li><code class="no-bg">__array_text(<span class="arg">t</span>, <span class="arg">n</span>, <span class="arg">s</span>)</code></li>
 140                 </ul>
 141             </td>
 142             <td>
 143                 <p>Statically-sized array, displayed as text</p>
 144                 <ul>
 145                     <li>
 146                         <code class="arg">t</code> array element C type
 147                         (always <code>char</code>)
 148                     </li>
 149                     <li><code class="arg">n</code> field name</li>
 150                     <li><code class="arg">s</code> number of elements</li>
 151                 </ul>
 152             </td>
 153         </tr>
 154         <tr>
 155             <td>
 156                 <ul>
 157                     <li><code class="no-bg">__dynamic_array(<span class="arg">t</span>, <span class="arg">n</span>, <span class="arg">s</span>)</code></li>
 158                 </ul>
 159             </td>
 160             <td>
 161                 <p>Dynamically-sized array, displayed in base&nbsp;10</p>
 162                 <ul>
 163                     <li>
 164                         <code class="arg">t</code> array element C type
 165                     </li>
 166                     <li><code class="arg">n</code> field name</li>
 167                     <li><code class="arg">s</code> length C expression</li>
 168                 </ul>
 169             </td>
 170         </tr>
 171         <tr>
 172             <td>
 173                 <ul>
 174                     <li><code class="no-bg">__dynamic_array_hex(<span class="arg">t</span>, <span class="arg">n</span>, <span class="arg">s</span>)</code></li>
 175                 </ul>
 176             </td>
 177             <td>
 178                 <p>Dynamically-sized array, displayed in base&nbsp;16</p>
 179                 <ul>
 180                     <li>
 181                         <code class="arg">t</code> array element C type
 182                     </li>
 183                     <li><code class="arg">n</code> field name</li>
 184                     <li><code class="arg">s</code> length C expression</li>
 185                 </ul>
 186             </td>
 187         </tr>
 188         <tr>
 189             <td>
 190                 <ul>
 191                     <li><code class="no-bg">__dynamic_array_text(<span class="arg">t</span>, <span class="arg">n</span>, <span class="arg">s</span>)</code></li>
 192                 </ul>
 193             </td>
 194             <td>
 195                 <p>Dynamically-sized array, displayed as text</p>
 196                 <ul>
 197                     <li>
 198                         <code class="arg">t</code> array element C type
 199                         (always <code>char</code>)
 200                     </li>
 201                     <li><code class="arg">n</code> field name</li>
 202                     <li><code class="arg">s</code> length C expression</li>
 203                 </ul>
 204             </td>
 205         </tr>
 206         <tr>
 207             <td>
 208                 <ul>
 209                     <li><code class="no-bg">__string(<span class="arg">n</span>, <span class="arg">s</span>)</code></li>
 210                 </ul>
 211             </td>
 212             <td>
 213                 <p>
 214                     Null-terminated string; undefined behavior
 215                     if <code class="arg">s</code> is <code>NULL</code>
 216                 </p>
 217                 <ul>
 218                     <li><code class="arg">n</code> field name</li>
 219                     <li><code class="arg">s</code> string source (pointer)</li>
 220                 </ul>
 221             </td>
 222         </tr>
 223     </tbody>
 224 </table>
 225
 226 The above macros should cover the majority of cases. For advanced items,
 227 see `probes/lttng-events.h`.