docs/reference/glib/html/gvariant-format-strings.html

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  22 <div class="refentry">
  23 <a name="gvariant-format-strings"></a><div class="titlepage"></div>
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  26 <h2><span class="refentrytitle">GVariant Format Strings</span></h2>
  27 <p>GVariant Format Strings — varargs conversion of GVariants</p>
  28 </td>
  29 <td valign="top" align="right"></td>
  30 </tr></table></div>
  31 <div class="refsect1">
  32 <a name="id483216"></a><h2>Variable Argument Conversions</h2>
  33 <p>
  34    This page attempts to document how to perform variable argument
  35    conversions with GVariant.
  36   </p>
  37 <p>
  38    Conversions occur according to format strings.  A format string is a two-way mapping between a single
  39    <a class="link" href="glib-GVariant.html#GVariant" title="GVariant">GVariant</a> value and one or more C values.
  40   </p>
  41 <p>
  42    A conversion from C values into a <a class="link" href="glib-GVariant.html#GVariant" title="GVariant">GVariant</a> value is made using the
  43    <a class="link" href="glib-GVariant.html#g-variant-new" title="g_variant_new ()"><code class="function">g_variant_new()</code></a> function.  A conversion from a
  44    <a class="link" href="glib-GVariant.html#GVariant" title="GVariant">GVariant</a> into C values is made using the
  45    <a class="link" href="glib-GVariant.html#g-variant-get" title="g_variant_get ()"><code class="function">g_variant_get()</code></a> function.
  46   </p>
  47 </div>
  48 <div class="refsect1">
  49 <a name="id621873"></a><h2>Syntax</h2>
  50 <p>
  51    This section exhaustively describes all possibilities for GVariant format strings.  There are no valid forms of
  52    format strings other than those described here.  Please note that the format string syntax is likely to expand in the
  53    future.
  54   </p>
  55 <p>
  56    Valid format strings have one of the following forms:
  57   </p>
  58 <div class="itemizedlist"><ul class="itemizedlist" type="disc">
  59 <li class="listitem"><p>any type string</p></li>
  60 <li class="listitem"><p>
  61      a type string prefixed with a '<code class="literal">@</code>'
  62     </p></li>
  63 <li class="listitem"><p>
  64      '<code class="literal">&amp;s</code>' '<code class="literal">&amp;o</code>', '<code class="literal">&amp;g</code>', '<code class="literal">^as</code>',
  65      '<code class="literal">^a&amp;s</code>', '<code class="literal">^ao</code>', '<code class="literal">^a&amp;o</code>','<code class="literal">^ay</code>',
  66      '<code class="literal">^&amp;ay</code>', '<code class="literal">^aay</code>' or '<code class="literal">^a&amp;ay</code>'.
  67     </p></li>
  68 <li class="listitem"><p>
  69      any format string, prefixed with an '<code class="literal">m</code>'
  70     </p></li>
  71 <li class="listitem"><p>
  72      a sequence of zero or more format strings strings, concatenated and enclosed in parentheses
  73     </p></li>
  74 <li class="listitem"><p>
  75      an opening brace, followed by two format strings, followed by a closing brace (subject to the constraint that the
  76      first format string correspond to a type valid for use as the key type of a dictionary)
  77     </p></li>
  78 </ul></div>
  79 </div>
  80 <div class="refsect1">
  81 <a name="id657332"></a><h2>Symbols</h2>
  82 <p>
  83     The following table describes the rough meaning of symbols that may appear inside a GVariant format string.  Each
  84     symbol is described in detail in its own section, including usage examples.
  85   </p>
  86 <div class="informaltable"><table border="1">
  87 <colgroup>
  88 <col class="col_0">
  89 <col class="col_1">
  90 </colgroup>
  91 <tbody>
  92 <tr>
  93 <td>
  94        <p>
  95         <span class="strong"><strong>Symbol</strong></span>
  96        </p>
  97       </td>
  98 <td>
  99        <p>
 100          <span class="strong"><strong>Meaning</strong></span>
 101        </p>
 102       </td>
 103 </tr>
 104 <tr>
 105 <td>
 106        <p>
 107         <span class="strong"><strong>
 108          <code class="literal">b</code>, <code class="literal">y</code>, <code class="literal">n</code>, <code class="literal">q</code>, <code class="literal">i</code>,
 109          <code class="literal">u</code>, <code class="literal">x</code>, <code class="literal">t</code>, <code class="literal">h</code>, <code class="literal">d</code>
 110         </strong></span>
 111        </p>
 112       </td>
 113 <td>
 114        <p>
 115         Used for building or deconstructing boolean, byte and numeric types.  See
 116         <a href="gvariant-format-strings.html#gvariant-format-strings-numeric-types">Numeric Types</a> below.
 117        </p>
 118       </td>
 119 </tr>
 120 <tr>
 121 <td>
 122        <p>
 123         <span class="strong"><strong>
 124          <code class="literal">s</code>, <code class="literal">o</code>, <code class="literal">g</code>
 125         </strong></span>
 126        </p>
 127       </td>
 128 <td>
 129        <p>
 130         Used for building or deconstructing string types.  See
 131         <a href="gvariant-format-strings.html#gvariant-format-strings-strings">Strings</a> below.
 132        </p>
 133       </td>
 134 </tr>
 135 <tr>
 136 <td>
 137        <p>
 138         <span class="strong"><strong><code class="literal">v</code></strong></span>
 139        </p>
 140       </td>
 141 <td>
 142        <p>
 143         Used for building or deconstructing variant types.  See
 144         <a href="gvariant-format-strings.html#gvariant-format-strings-variants">Variants</a> below.
 145        </p>
 146       </td>
 147 </tr>
 148 <tr>
 149 <td>
 150        <p>
 151         <span class="strong"><strong>
 152          <code class="literal">a</code>
 153         </strong></span>
 154        </p>
 155       </td>
 156 <td>
 157        <p>
 158         Used for building or deconstructing arrays.  See
 159         <a href="gvariant-format-strings.html#gvariant-format-strings-arrays">Arrays</a> below.
 160        </p>
 161       </td>
 162 </tr>
 163 <tr>
 164 <td>
 165        <p>
 166         <span class="strong"><strong>
 167          <code class="literal">m</code>
 168         </strong></span>
 169        </p>
 170       </td>
 171 <td>
 172        <p>
 173          Used for building or deconstructing maybe types.  See
 174          <a href="gvariant-format-strings.html#gvariant-format-strings-maybe-types">Maybe Types</a> below.
 175        </p>
 176       </td>
 177 </tr>
 178 <tr>
 179 <td>
 180        <p>
 181         <span class="strong"><strong>
 182          <code class="literal">()</code>
 183         </strong></span>
 184        </p>
 185       </td>
 186 <td>
 187        <p>
 188          Used for building or deconstructing tuples.  See
 189          <a href="gvariant-format-strings.html#gvariant-format-strings-tuples">Tuples</a> below.
 190        </p>
 191       </td>
 192 </tr>
 193 <tr>
 194 <td>
 195        <p>
 196         <span class="strong"><strong>
 197          <code class="literal">{}</code>
 198         </strong></span>
 199        </p>
 200       </td>
 201 <td>
 202        <p>
 203         Used for building or deconstructing dictionary entries. See
 204         <a href="gvariant-format-strings.html#gvariant-format-strings-dictionaries">Dictionaries</a> below.
 205        </p>
 206       </td>
 207 </tr>
 208 <tr>
 209 <td>
 210        <p>
 211         <span class="strong"><strong>
 212          <code class="literal">@</code>
 213         </strong></span>
 214        </p>
 215       </td>
 216 <td>
 217        <p>
 218         Used as a prefix on a GVariant type string (not format string).  Denotes that a pointer to a
 219         <a class="link" href="glib-GVariant.html#GVariant" title="GVariant">GVariant</a> should be used in place of the normal C type or types.  For
 220         <a class="link" href="glib-GVariant.html#g-variant-new" title="g_variant_new ()"><code class="function">g_variant_new()</code></a> this means that you must pass a
 221         non-<a class="link" href="glib-Standard-Macros.html#NULL:CAPS" title="NULL"><code class="literal">NULL</code></a> <code class="code">(<a class="link" href="glib-GVariant.html#GVariant" title="GVariant">GVariant</a>
 222         *)</code>; if it is a floating reference, ownership will be taken, as
 223         if by using <a class="link" href="glib-GVariant.html#g-variant-ref-sink" title="g_variant_ref_sink ()"><code class="function">g_variant_ref_sink()</code></a>.
 224         For <a class="link" href="glib-GVariant.html#g-variant-get" title="g_variant_get ()"><code class="function">g_variant_get()</code></a> this means that you
 225         must pass a pointer to a <code class="code">(<a class="link" href="glib-GVariant.html#GVariant" title="GVariant">GVariant</a> *)</code> for the value to be returned
 226         by reference or <a class="link" href="glib-Standard-Macros.html#NULL:CAPS" title="NULL"><code class="literal">NULL</code></a> to ignore the value.  See
 227         <a href="gvariant-format-strings.html#gvariant-format-strings-gvariant"><code class="code">GVariant *</code></a> below.
 228        </p>
 229       </td>
 230 </tr>
 231 <tr>
 232 <td>
 233        <p>
 234         <span class="strong"><strong>
 235          <code class="literal">*</code>, <code class="literal">?</code>, <code class="literal">r</code>
 236         </strong></span>
 237        </p>
 238       </td>
 239 <td>
 240        <p>
 241         Exactly equivalent to <code class="literal">@*</code>, <code class="literal">@?</code> and <code class="literal">@r</code>.  Provided only for
 242         completeness so that all GVariant type strings can be used also as format strings.  See <a href="gvariant-format-strings.html#gvariant-format-strings-gvariant"><code class="code">GVariant *</code></a> below.
 243        </p>
 244       </td>
 245 </tr>
 246 <tr>
 247 <td>
 248        <p>
 249         <span class="strong"><strong><code class="literal">&amp;</code></strong></span>
 250        </p>
 251       </td>
 252 <td>
 253        <p>
 254         Used as a prefix on a GVariant type string (not format string).  Denotes that a C pointer to serialised data
 255         should be used in place of the normal C type.  See
 256         <a href="gvariant-format-strings.html#gvariant-format-strings-pointers">Pointers</a> below.
 257        </p>
 258       </td>
 259 </tr>
 260 <tr>
 261 <td>
 262        <p>
 263         <span class="strong"><strong><code class="literal">^</code></strong></span>
 264        </p>
 265       </td>
 266 <td>
 267        <p>
 268         Used as a prefix on some specific types of format strings.  See
 269         <a href="gvariant-format-strings.html#gvariant-format-strings-convenience">Convenience Conversions</a> below.
 270        </p>
 271       </td>
 272 </tr>
 273 </tbody>
 274 </table></div>
 275 <div class="refsect2">
 276 <a name="gvariant-format-strings-numeric-types"></a><h3>Numeric Types</h3>
 277 <p>
 278     <span class="strong"><strong>
 279      Characters: <code class="literal">b</code>, <code class="literal">y</code>, <code class="literal">n</code>, <code class="literal">q</code>,
 280      <code class="literal">i</code>, <code class="literal">u</code>, <code class="literal">x</code>, <code class="literal">t</code>, <code class="literal">h</code>,
 281      <code class="literal">d</code>
 282     </strong></span>
 283    </p>
 284 <p>
 285     Variable argument conversions from numeric types work in the most obvious way possible.  Upon encountering one of
 286     these characters, <a class="link" href="glib-GVariant.html#g-variant-new" title="g_variant_new ()"><code class="function">g_variant_new()</code></a> takes the equivalent C
 287     type as an argument.  <a class="link" href="glib-GVariant.html#g-variant-get" title="g_variant_get ()"><code class="function">g_variant_get()</code></a> takes a pointer to
 288     the equivalent C type (or <a class="link" href="glib-Standard-Macros.html#NULL:CAPS" title="NULL"><code class="literal">NULL</code></a> to ignore the value).
 289    </p>
 290 <p>
 291     The equivalent C types are as follows:
 292    </p>
 293 <div class="informaltable"><table border="1">
 294 <colgroup>
 295 <col class="col_0">
 296 <col class="col_1">
 297 </colgroup>
 298 <tbody>
 299 <tr>
 300 <td>
 301         <p>
 302           <span class="strong"><strong>Character</strong></span>
 303         </p>
 304        </td>
 305 <td>
 306         <p>
 307           <span class="strong"><strong>Equivalent C type</strong></span>
 308         </p>
 309        </td>
 310 </tr>
 311 <tr>
 312 <td>
 313         <p>
 314          <span class="strong"><strong>
 315           <code class="literal">b</code>
 316          </strong></span>
 317         </p>
 318        </td>
 319 <td>
 320         <p>
 321          <a class="link" href="glib-Basic-Types.html#gboolean" title="gboolean"><span class="type">gboolean</span></a>
 322         </p>
 323        </td>
 324 </tr>
 325 <tr>
 326 <td>
 327         <p>
 328          <span class="strong"><strong>
 329           <code class="literal">y</code>
 330          </strong></span>
 331         </p>
 332        </td>
 333 <td>
 334         <p>
 335          <a class="link" href="glib-Basic-Types.html#guchar" title="guchar"><span class="type">guchar</span></a>
 336         </p>
 337        </td>
 338 </tr>
 339 <tr>
 340 <td>
 341         <p>
 342          <span class="strong"><strong>
 343           <code class="literal">n</code>
 344          </strong></span>
 345         </p>
 346        </td>
 347 <td>
 348         <p>
 349          <a class="link" href="glib-Basic-Types.html#gint16" title="gint16"><span class="type">gint16</span></a>
 350         </p>
 351        </td>
 352 </tr>
 353 <tr>
 354 <td>
 355         <p>
 356          <span class="strong"><strong>
 357           <code class="literal">q</code>
 358          </strong></span>
 359         </p>
 360        </td>
 361 <td>
 362         <p>
 363          <a class="link" href="glib-Basic-Types.html#guint16" title="guint16"><span class="type">guint16</span></a>
 364         </p>
 365        </td>
 366 </tr>
 367 <tr>
 368 <td>
 369         <p>
 370          <span class="strong"><strong>
 371           <code class="literal">i</code>
 372          </strong></span>
 373         </p>
 374        </td>
 375 <td>
 376         <p>
 377          <a class="link" href="glib-Basic-Types.html#gint32" title="gint32"><span class="type">gint32</span></a>
 378         </p>
 379        </td>
 380 </tr>
 381 <tr>
 382 <td>
 383         <p>
 384          <span class="strong"><strong>
 385           <code class="literal">u</code>
 386          </strong></span>
 387         </p>
 388        </td>
 389 <td>
 390         <p>
 391          <a class="link" href="glib-Basic-Types.html#guint32" title="guint32"><span class="type">guint32</span></a>
 392         </p>
 393        </td>
 394 </tr>
 395 <tr>
 396 <td>
 397         <p>
 398          <span class="strong"><strong>
 399           <code class="literal">x</code>
 400          </strong></span>
 401         </p>
 402        </td>
 403 <td>
 404         <p>
 405          <a class="link" href="glib-Basic-Types.html#gint64" title="gint64"><span class="type">gint64</span></a>
 406         </p>
 407        </td>
 408 </tr>
 409 <tr>
 410 <td>
 411         <p>
 412          <span class="strong"><strong>
 413           <code class="literal">t</code>
 414          </strong></span>
 415         </p>
 416        </td>
 417 <td>
 418         <p>
 419          <a class="link" href="glib-Basic-Types.html#guint64" title="guint64"><span class="type">guint64</span></a>
 420         </p>
 421        </td>
 422 </tr>
 423 <tr>
 424 <td>
 425         <p>
 426          <span class="strong"><strong>
 427           <code class="literal">h</code>
 428          </strong></span>
 429         </p>
 430        </td>
 431 <td>
 432         <p>
 433          <a class="link" href="glib-Basic-Types.html#gint32" title="gint32"><span class="type">gint32</span></a>
 434         </p>
 435        </td>
 436 </tr>
 437 <tr>
 438 <td>
 439         <p>
 440          <span class="strong"><strong>
 441           <code class="literal">d</code>
 442          </strong></span>
 443         </p>
 444        </td>
 445 <td>
 446         <p>
 447          <a class="link" href="glib-Basic-Types.html#gdouble" title="gdouble"><span class="type">gdouble</span></a>
 448         </p>
 449        </td>
 450 </tr>
 451 </tbody>
 452 </table></div>
 453 <p>
 454     Note that in C, small integer types in variable argument lists are promoted up to <a class="link" href="glib-Basic-Types.html#gint" title="gint"><span class="type">int</span></a> or <a class="link" href="glib-Basic-Types.html#guint" title="guint"><span class="type">unsigned int</span></a> as appropriate, and
 455     read back accordingly.  <a class="link" href="glib-Basic-Types.html#gint" title="gint"><span class="type">int</span></a> is 32 bits on every platform on which GLib is
 456     currently suported.  This means that you can use C expressions of type <a class="link" href="glib-Basic-Types.html#gint" title="gint"><span class="type">int</span></a>
 457     with <a class="link" href="glib-GVariant.html#g-variant-new" title="g_variant_new ()"><code class="function">g_variant_new()</code></a> and format characters
 458     '<code class="literal">b</code>', '<code class="literal">y</code>', '<code class="literal">n</code>', '<code class="literal">q</code>',
 459     '<code class="literal">i</code>', '<code class="literal">u</code>' and '<code class="literal">h</code>'.  Specifically, you can use integer
 460     literals with these characters.
 461    </p>
 462 <p>
 463     When using the '<code class="literal">x</code>' and '<code class="literal">t</code>' characters, you must ensure that the value that you
 464     provide is 64 bit.  This means that you should use a cast or make use of the
 465     <a class="link" href="glib-Basic-Types.html#G-GINT64-CONSTANT:CAPS" title="G_GINT64_CONSTANT()"><code class="literal">G_GINT64_CONSTANT</code></a> or
 466     <a class="link" href="glib-Basic-Types.html#G-GUINT64-CONSTANT:CAPS" title="G_GUINT64_CONSTANT()"><code class="literal">G_GUINT64_CONSTANT</code></a> macros.
 467    </p>
 468 <p>
 469     No type promotion occurs when using <a class="link" href="glib-GVariant.html#g-variant-get" title="g_variant_get ()"><code class="function">g_variant_get()</code></a> since
 470     it operates with pointers.  The pointers must always point to a memory region of exactly the correct size.
 471    </p>
 472 <div class="refsect3">
 473 <a name="id620659"></a><h4>Examples</h4>
 474 <div class="informalexample">
 475   <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
 476     <tbody>
 477       <tr>
 478         <td class="listing_lines" align="right"><pre>1
 479 2
 480 3
 481 4
 482 5
 483 6
 484 7
 485 8
 486 9
 487 10
 488 11
 489 12
 490 13
 491 14
 492 15
 493 16
 494 17
 495 18</pre></td>
 496         <td class="listing_code"><pre class="programlisting"><span class="usertype">GVariant</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">value1</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">value2</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">value3</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">value4</span><span class="symbol">;</span>
 497
 498 <span class="normal">value1 </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new">g_variant_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"y"</span><span class="symbol">,</span><span class="normal"> </span><span class="number">200</span><span class="symbol">);</span>
 499 <span class="normal">value2 </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new">g_variant_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"b"</span><span class="symbol">,</span><span class="normal"> <a href="glib-Standard-Macros.html#TRUE:CAPS">TRUE</a></span><span class="symbol">);</span>
 500 <span class="normal">value3 </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new">g_variant_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"d"</span><span class="symbol">,</span><span class="normal"> </span><span class="number">37.5</span><span class="symbol">):</span>
 501 <span class="normal">value4 </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new">g_variant_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"x"</span><span class="symbol">,</span><span class="normal"> </span><span class="function"><a href="glib-Basic-Types.html#G-GINT64-CONSTANT:CAPS">G_GINT64_CONSTANT</a></span><span class="normal"> </span><span class="symbol">(</span><span class="number">998877665544332211</span><span class="symbol">));</span>
 502
 503 <span class="cbracket">{</span>
 504 <span class="normal">  </span><span class="usertype">gdouble</span><span class="normal"> floating</span><span class="symbol">;</span>
 505 <span class="normal">  </span><span class="usertype">gboolean</span><span class="normal"> truth</span><span class="symbol">;</span>
 506 <span class="normal">  </span><span class="usertype">gint64</span><span class="normal"> bignum</span><span class="symbol">;</span>
 507
 508
 509 <span class="normal">  </span><span class="function"><a href="glib-GVariant.html#g-variant-get">g_variant_get</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">value1</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"y"</span><span class="symbol">,</span><span class="normal"> <a href="glib-Standard-Macros.html#NULL:CAPS">NULL</a></span><span class="symbol">);</span><span class="normal">      </span><span class="comment">/* ignore the value. */</span>
 510 <span class="normal">  </span><span class="function"><a href="glib-GVariant.html#g-variant-get">g_variant_get</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">value2</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"b"</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">truth</span><span class="symbol">);</span>
 511 <span class="normal">  </span><span class="function"><a href="glib-GVariant.html#g-variant-get">g_variant_get</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">value3</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"d"</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">floating</span><span class="symbol">);</span>
 512 <span class="normal">  </span><span class="function"><a href="glib-GVariant.html#g-variant-get">g_variant_get</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">value4</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"x"</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">bignum</span><span class="symbol">);</span>
 513 <span class="cbracket">}</span></pre></td>
 514       </tr>
 515     </tbody>
 516   </table>
 517 </div>
 518
 519 </div>
 520 </div>
 521 <hr>
 522 <div class="refsect2">
 523 <a name="gvariant-format-strings-strings"></a><h3>Strings</h3>
 524 <p>
 525     <span class="strong"><strong>
 526      Characters: <code class="literal">s</code>, <code class="literal">o</code>, <code class="literal">g</code>
 527     </strong></span>
 528    </p>
 529 <p>
 530     String conversions occur to and from standard nul-terminated C strings.  Upon encountering an
 531     '<code class="literal">s</code>', '<code class="literal">o</code>' or '<code class="literal">g</code>' in a format string,
 532     <a class="link" href="glib-GVariant.html#g-variant-new" title="g_variant_new ()"><code class="function">g_variant_new()</code></a> takes a <code class="code">(const
 533     <a class="link" href="glib-Basic-Types.html#gchar" title="gchar">gchar</a> *)</code> and makes a copy of it.
 534     <a class="link" href="glib-Standard-Macros.html#NULL:CAPS" title="NULL"><code class="literal">NULL</code></a> is not a valid string.  If the '<code class="literal">o</code>' or
 535     '<code class="literal">g</code>' characters are used, care must be taken to ensure that the passed string is a valid DBus
 536     object path or DBus type signature, respectively.
 537    </p>
 538 <p>
 539     Upon encounting '<code class="literal">s</code>', '<code class="literal">o</code>' or '<code class="literal">g</code>', <a class="link" href="glib-GVariant.html#g-variant-get" title="g_variant_get ()"><code class="function">g_variant_get()</code></a> takes a pointer to a
 540     <code class="code">(<a class="link" href="glib-Basic-Types.html#gchar" title="gchar">gchar</a> *)</code> (ie: <code class="code">(<a class="link" href="glib-Basic-Types.html#gchar" title="gchar">gchar</a> **)</code>) and
 541     sets it to a newly-allocated copy of the string.  It is appropriate to free this copy using
 542     <a class="link" href="glib-Memory-Allocation.html#g-free" title="g_free ()"><code class="function">g_free()</code></a>.
 543     <a class="link" href="glib-Standard-Macros.html#NULL:CAPS" title="NULL"><code class="literal">NULL</code></a> may also be passed to indicate that the value of the
 544     string should be ignored (in which case no copy is made).
 545    </p>
 546 <div class="refsect3">
 547 <a name="id521416"></a><h4>Examples</h4>
 548 <div class="informalexample">
 549   <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
 550     <tbody>
 551       <tr>
 552         <td class="listing_lines" align="right"><pre>1
 553 2
 554 3
 555 4
 556 5
 557 6
 558 7
 559 8
 560 9
 561 10
 562 11
 563 12
 564 13
 565 14
 566 15
 567 16
 568 17</pre></td>
 569         <td class="listing_code"><pre class="programlisting"><span class="usertype">GVariant</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">value1</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">value2</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">value3</span><span class="symbol">;</span>
 570
 571 <span class="normal">value1 </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new">g_variant_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"s"</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"hello world!"</span><span class="symbol">);</span>
 572 <span class="normal">value2 </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new">g_variant_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"o"</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"/must/be/a/valid/path"</span><span class="symbol">);</span>
 573 <span class="normal">value3 </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new">g_variant_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"g"</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"iias"</span><span class="symbol">);</span>
 574
 575 <span class="preproc">#if</span><span class="normal"> </span><span class="number">0</span>
 576 <span class="normal">  </span><span class="function"><a href="glib-GVariant.html#g-variant-new">g_variant_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"s"</span><span class="symbol">,</span><span class="normal"> <a href="glib-Standard-Macros.html#NULL:CAPS">NULL</a></span><span class="symbol">);</span><span class="normal">      </span><span class="comment">/* not valid: NULL is not a string. */</span>
 577 <span class="preproc">#endif</span>
 578
 579 <span class="cbracket">{</span>
 580 <span class="normal">  </span><span class="usertype">gchar</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">result</span><span class="symbol">;</span>
 581
 582 <span class="normal">  </span><span class="function"><a href="glib-GVariant.html#g-variant-get">g_variant_get</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">value1</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"s"</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">result</span><span class="symbol">);</span>
 583 <span class="normal">  </span><span class="function"><a href="glib-Warnings-and-Assertions.html#g-print">g_print</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"It was '%s'</span><span class="specialchar">\n</span><span class="string">"</span><span class="symbol">,</span><span class="normal"> result</span><span class="symbol">);</span>
 584 <span class="normal">  </span><span class="function"><a href="glib-Memory-Allocation.html#g-free">g_free</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">result</span><span class="symbol">);</span>
 585 <span class="cbracket">}</span></pre></td>
 586       </tr>
 587     </tbody>
 588   </table>
 589 </div>
 590
 591 </div>
 592 </div>
 593 <hr>
 594 <div class="refsect2">
 595 <a name="gvariant-format-strings-variants"></a><h3>Variants</h3>
 596 <p>
 597     <span class="strong"><strong>
 598      Characters: <code class="literal">v</code>
 599     </strong></span>
 600    </p>
 601 <p>
 602     Upon encountering a '<code class="literal">v</code>',
 603     <a class="link" href="glib-GVariant.html#g-variant-new" title="g_variant_new ()"><code class="function">g_variant_new()</code></a> takes a <code class="code">(<a class="link" href="glib-GVariant.html#GVariant" title="GVariant">GVariant</a> *)</code>.  The value of the
 604     <a class="link" href="glib-GVariant.html#GVariant" title="GVariant"><span class="type">GVariant</span></a> is used as the contents of the variant value.
 605    </p>
 606 <p>
 607     Upon encountering a '<code class="literal">v</code>', <a class="link" href="glib-GVariant.html#g-variant-get" title="g_variant_get ()"><code class="function">g_variant_get()</code></a> takes a pointer to a
 608     <code class="code">(<a class="link" href="glib-GVariant.html#GVariant" title="GVariant">GVariant</a> *)</code> (ie: <code class="code">(<a class="link" href="glib-GVariant.html#GVariant" title="GVariant">GVariant</a> **)
 609     </code>).  It is set to a new reference to a <a class="link" href="glib-GVariant.html#GVariant" title="GVariant"><span class="type">GVariant</span></a> instance
 610     containing the contents of the variant value.  It is appropriate to free this reference using
 611     <a class="link" href="glib-GVariant.html#g-variant-unref" title="g_variant_unref ()"><code class="function">g_variant_unref()</code></a>.
 612     <a class="link" href="glib-Standard-Macros.html#NULL:CAPS" title="NULL"><code class="literal">NULL</code></a> may also be passed to indicate that the value should be
 613     ignored (in which case no new reference is created).
 614    </p>
 615 <div class="refsect3">
 616 <a name="id620998"></a><h4>Examples</h4>
 617 <div class="informalexample">
 618   <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
 619     <tbody>
 620       <tr>
 621         <td class="listing_lines" align="right"><pre>1
 622 2
 623 3
 624 4
 625 5
 626 6
 627 7
 628 8
 629 9</pre></td>
 630         <td class="listing_code"><pre class="programlisting"><span class="usertype">GVariant</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">x</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">y</span><span class="symbol">;</span>
 631
 632 <span class="comment">/* the following two lines are equivalent: */</span>
 633 <span class="normal">x </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new">g_variant_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"v"</span><span class="symbol">,</span><span class="normal"> y</span><span class="symbol">);</span>
 634 <span class="normal">x </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new-variant">g_variant_new_variant</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">y</span><span class="symbol">);</span>
 635
 636 <span class="comment">/* as are these: */</span>
 637 <span class="function"><a href="glib-GVariant.html#g-variant-get">g_variant_get</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">x</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"v"</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">y</span><span class="symbol">);</span>
 638 <span class="normal">y </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-get-variant">g_variant_get_variant</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">x</span><span class="symbol">);</span></pre></td>
 639       </tr>
 640     </tbody>
 641   </table>
 642 </div>
 643
 644 </div>
 645 </div>
 646 <hr>
 647 <div class="refsect2">
 648 <a name="gvariant-format-strings-arrays"></a><h3>Arrays</h3>
 649 <p>
 650     <span class="strong"><strong>
 651      Characters: <code class="literal">a</code>
 652     </strong></span>
 653    </p>
 654 <p>
 655     Upon encountering an '<code class="literal">a</code>' character followed by a type string,
 656     <a class="link" href="glib-GVariant.html#g-variant-new" title="g_variant_new ()"><code class="function">g_variant_new()</code></a> will take a
 657     <code class="code">(<a class="link" href="glib-GVariant.html#GVariantBuilder" title="struct GVariantBuilder">GVariantBuilder</a> *)</code> that has been created as an array builder
 658     for an array of the type given in the type string.  The builder will have
 659     <a class="link" href="glib-GVariant.html#g-variant-builder-end" title="g_variant_builder_end ()"><code class="function">g_variant_builder_end()</code></a> called on it and the
 660     result will be used as the value.  As a special exception, if the given type string is a definite type, then
 661     <a class="link" href="glib-Standard-Macros.html#NULL:CAPS" title="NULL"><code class="literal">NULL</code></a> may be given to mean an empty array of that type.
 662    </p>
 663 <p>
 664     Upon encountering an '<code class="literal">a</code>' character followed by a type string,
 665     <a class="link" href="glib-GVariant.html#g-variant-get" title="g_variant_get ()"><code class="function">g_variant_get()</code></a> will take a pointer to a
 666     <code class="code">(<a class="link" href="glib-GVariant.html#GVariantIter" title="struct GVariantIter">GVariantIter</a> *)</code> (ie:
 667     <code class="code">(<a class="link" href="glib-GVariant.html#GVariantIter" title="struct GVariantIter">GVariantIter</a> **)</code>).
 668     A new heap-allocated iterator is created and returned, initialised for iterating over the elements of the array.
 669     This iterator should be freed when you are done with it, using
 670     <a class="link" href="glib-GVariant.html#g-variant-iter-free" title="g_variant_iter_free ()"><code class="function">g_variant_iter_free()</code></a>.
 671     <a class="link" href="glib-Standard-Macros.html#NULL:CAPS" title="NULL"><code class="literal">NULL</code></a> may also be given to indicate that the value of the array
 672     should be ignored.
 673    </p>
 674 <div class="refsect3">
 675 <a name="id465923"></a><h4>Examples</h4>
 676 <div class="informalexample">
 677   <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
 678     <tbody>
 679       <tr>
 680         <td class="listing_lines" align="right"><pre>1
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 702         <td class="listing_code"><pre class="programlisting"><span class="usertype">GVariantBuilder</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">builder</span><span class="symbol">;</span>
 703 <span class="usertype">GVariant</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">value</span><span class="symbol">;</span>
 704
 705 <span class="normal">builder </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-builder-new">g_variant_builder_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="function"><a href="glib-GVariantType.html#G-VARIANT-TYPE:CAPS">G_VARIANT_TYPE</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"as"</span><span class="symbol">));</span>
 706 <span class="function"><a href="glib-GVariant.html#g-variant-builder-add">g_variant_builder_add</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">builder</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"s"</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"when"</span><span class="symbol">);</span>
 707 <span class="function"><a href="glib-GVariant.html#g-variant-builder-add">g_variant_builder_add</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">builder</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"s"</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"in"</span><span class="symbol">);</span>
 708 <span class="function"><a href="glib-GVariant.html#g-variant-builder-add">g_variant_builder_add</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">builder</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"s"</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"the"</span><span class="symbol">);</span>
 709 <span class="function"><a href="glib-GVariant.html#g-variant-builder-add">g_variant_builder_add</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">builder</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"s"</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"course"</span><span class="symbol">);</span>
 710 <span class="normal">value </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new">g_variant_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"as"</span><span class="symbol">,</span><span class="normal"> builder</span><span class="symbol">);</span>
 711 <span class="function"><a href="glib-GVariant.html#g-variant-builder-unref">g_variant_builder_unref</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">builder</span><span class="symbol">);</span>
 712
 713 <span class="cbracket">{</span>
 714 <span class="normal">  </span><span class="usertype">GVariantIter</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">iter</span><span class="symbol">;</span>
 715 <span class="normal">  </span><span class="usertype">gchar</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">str</span><span class="symbol">;</span>
 716
 717 <span class="normal">  </span><span class="function"><a href="glib-GVariant.html#g-variant-get">g_variant_get</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">value</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"as"</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">iter</span><span class="symbol">);</span>
 718 <span class="normal">  </span><span class="keyword">while</span><span class="normal"> </span><span class="symbol">(</span><span class="function"><a href="glib-GVariant.html#g-variant-iter-loop">g_variant_iter_loop</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">iter</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"s"</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">str</span><span class="symbol">))</span>
 719 <span class="normal">    </span><span class="function"><a href="glib-Warnings-and-Assertions.html#g-print">g_print</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"%s</span><span class="specialchar">\n</span><span class="string">"</span><span class="symbol">,</span><span class="normal"> str</span><span class="symbol">);</span>
 720 <span class="normal">  </span><span class="function"><a href="glib-GVariant.html#g-variant-iter-free">g_variant_iter_free</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">iter</span><span class="symbol">);</span>
 721 <span class="cbracket">}</span>
 722
 723 <span class="function"><a href="glib-GVariant.html#g-variant-unref">g_variant_unref</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">value</span><span class="symbol">);</span></pre></td>
 724       </tr>
 725     </tbody>
 726   </table>
 727 </div>
 728
 729 </div>
 730 </div>
 731 <hr>
 732 <div class="refsect2">
 733 <a name="gvariant-format-strings-maybe-types"></a><h3>Maybe Types</h3>
 734 <p>
 735     <span class="strong"><strong>
 736      Characters: <code class="literal">m</code>
 737     </strong></span>
 738    </p>
 739 <p>
 740     Maybe types are handled in two separate ways depending on the format string that follows the
 741     '<code class="literal">m</code>'.  The method that is used currently depends entirely on the character immediately following the
 742     '<code class="literal">m</code>'.
 743    </p>
 744 <p>
 745     The first way is used with format strings starting with '<code class="literal">a</code>', '<code class="literal">s</code>',
 746     '<code class="literal">o</code>', '<code class="literal">g</code>', '<code class="literal">v</code>', '<code class="literal">@</code>',
 747     '<code class="literal">*</code>', '<code class="literal">?</code>', '<code class="literal">r</code>', '<code class="literal">&amp;</code>', or
 748     '<code class="literal">^</code>'.  In all of these cases, for non-maybe types,
 749     <a class="link" href="glib-GVariant.html#g-variant-new" title="g_variant_new ()"><code class="function">g_variant_new()</code></a> takes a pointer to a
 750     non-<a class="link" href="glib-Standard-Macros.html#NULL:CAPS" title="NULL"><code class="literal">NULL</code></a> value and
 751     <a class="link" href="glib-GVariant.html#g-variant-get" title="g_variant_get ()"><code class="function">g_variant_get()</code></a> returns (by reference) a
 752     non-<a class="link" href="glib-Standard-Macros.html#NULL:CAPS" title="NULL"><code class="literal">NULL</code></a> pointer.  When any of these format strings are
 753     prefixed with an '<code class="literal">m</code>', the type of arguments that are collected does not change in any way, but
 754     <a class="link" href="glib-Standard-Macros.html#NULL:CAPS" title="NULL"><code class="literal">NULL</code></a> becomes a permissable value, to indicate the Nothing case.
 755    </p>
 756 <p>
 757     Note that the "special exception" introduced in the array section for constructing empty arrays is ignored
 758     here.  Using a <code class="literal">NULL</code> pointer with the format string '<code class="literal">mas</code>' constructs
 759     the Nothing value -- not an empty array.
 760    </p>
 761 <p>
 762     The second way is used with all other format strings.  For
 763     <a class="link" href="glib-GVariant.html#g-variant-new" title="g_variant_new ()"><code class="function">g_variant_new()</code></a> an additional
 764     <a class="link" href="glib-Basic-Types.html#gboolean" title="gboolean"><span class="type">gboolean</span></a> argument is collected and for
 765     <a class="link" href="glib-GVariant.html#g-variant-get" title="g_variant_get ()"><code class="function">g_variant_get()</code></a> an additional
 766     <code class="code">(<a class="link" href="glib-Basic-Types.html#gboolean" title="gboolean">gboolean</a> *)</code>.  Following this argument, the arguments that are normally
 767     collected for the equivalent non-maybe type will be collected.
 768    </p>
 769 <p>
 770     If <a class="link" href="glib-Standard-Macros.html#FALSE:CAPS" title="FALSE"><code class="literal">FALSE</code></a> is given to
 771     <a class="link" href="glib-GVariant.html#g-variant-new" title="g_variant_new ()"><code class="function">g_variant_new()</code></a> then the Nothing value is constructed and
 772     the collected arguments are ignored.  Otherwise (if <a class="link" href="glib-Standard-Macros.html#TRUE:CAPS" title="TRUE"><code class="literal">TRUE</code></a> was
 773     given), the arguments are used in the normal way to create the Just value.
 774    </p>
 775 <p>
 776     If <a class="link" href="glib-Standard-Macros.html#NULL:CAPS" title="NULL"><code class="literal">NULL</code></a> is given to
 777     <a class="link" href="glib-GVariant.html#g-variant-get" title="g_variant_get ()"><code class="function">g_variant_get()</code></a> then the value is ignored.  If a
 778     non-<a class="link" href="glib-Standard-Macros.html#NULL:CAPS" title="NULL"><code class="literal">NULL</code></a> pointer is given then it is used to return by reference
 779     whether the value was Just.  In the case that the value was Just, the
 780     <a class="link" href="glib-Basic-Types.html#gboolean" title="gboolean"><span class="type">gboolean</span></a> will be set to
 781     <a class="link" href="glib-Standard-Macros.html#TRUE:CAPS" title="TRUE"><code class="literal">TRUE</code></a> and the value will be stored in the arguments in the usual
 782     way.  In the case that the value was Nothing, the <a class="link" href="glib-Basic-Types.html#gboolean" title="gboolean"><span class="type">gboolean</span></a> will be set to
 783     <a class="link" href="glib-Standard-Macros.html#FALSE:CAPS" title="FALSE"><code class="literal">FALSE</code></a> and the arguments will be collected in the normal way
 784     but have their values set to binary zero.
 785    </p>
 786 <div class="refsect3">
 787 <a name="id452005"></a><h4>Examples</h4>
 788 <div class="informalexample">
 789   <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
 790     <tbody>
 791       <tr>
 792         <td class="listing_lines" align="right"><pre>1
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 846 55</pre></td>
 847         <td class="listing_code"><pre class="programlisting"><span class="usertype">GVariant</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">value1</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">value2</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">value3</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">value4</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">value5</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">value6</span><span class="symbol">;</span>
 848 <span class="normal">value1 </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new">g_variant_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"ms"</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"Hello world"</span><span class="symbol">);</span>
 849 <span class="normal">value2 </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new">g_variant_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"ms"</span><span class="symbol">,</span><span class="normal"> <a href="glib-Standard-Macros.html#NULL:CAPS">NULL</a></span><span class="symbol">);</span>
 850 <span class="normal">value3 </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new">g_variant_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"(m(ii)s)"</span><span class="symbol">,</span><span class="normal"> <a href="glib-Standard-Macros.html#TRUE:CAPS">TRUE</a></span><span class="symbol">,</span><span class="normal"> </span><span class="number">123</span><span class="symbol">,</span><span class="normal"> </span><span class="number">456</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"Done"</span><span class="symbol">);</span>
 851 <span class="normal">value4 </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new">g_variant_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"(m(ii)s)"</span><span class="symbol">,</span><span class="normal"> <a href="glib-Standard-Macros.html#FALSE:CAPS">FALSE</a></span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">-</span><span class="number">1</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">-</span><span class="number">1</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"Done"</span><span class="symbol">);</span><span class="normal">          </span><span class="comment">/* both '-1' are ignored. */</span>
 852 <span class="normal">value5 </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new">g_variant_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"(m@(ii)s)"</span><span class="symbol">,</span><span class="normal"> <a href="glib-Standard-Macros.html#NULL:CAPS">NULL</a></span><span class="symbol">,</span><span class="normal"> </span><span class="string">"Done"</span><span class="symbol">);</span>
 853
 854 <span class="cbracket">{</span>
 855 <span class="normal">  </span><span class="usertype">GVariant</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">contents</span><span class="symbol">;</span>
 856 <span class="normal">  </span><span class="keyword">const</span><span class="normal"> </span><span class="usertype">gchar</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">cstr</span><span class="symbol">;</span>
 857 <span class="normal">  </span><span class="usertype">gboolean</span><span class="normal"> just</span><span class="symbol">;</span>
 858 <span class="normal">  </span><span class="usertype">gint32</span><span class="normal"> x</span><span class="symbol">,</span><span class="normal"> y</span><span class="symbol">;</span>
 859 <span class="normal">  </span><span class="usertype">gchar</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">str</span><span class="symbol">;</span>
 860
 861 <span class="normal">  </span><span class="function"><a href="glib-GVariant.html#g-variant-get">g_variant_get</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">value1</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"ms"</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">str</span><span class="symbol">);</span>
 862 <span class="normal">  </span><span class="keyword">if</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">str </span><span class="symbol">!=</span><span class="normal"> <a href="glib-Standard-Macros.html#NULL:CAPS">NULL</a></span><span class="symbol">)</span>
 863 <span class="normal">    </span><span class="function"><a href="glib-Warnings-and-Assertions.html#g-print">g_print</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"str: %s</span><span class="specialchar">\n</span><span class="string">"</span><span class="symbol">,</span><span class="normal"> str</span><span class="symbol">);</span>
 864 <span class="normal">  </span><span class="keyword">else</span>
 865 <span class="normal">    </span><span class="function"><a href="glib-Warnings-and-Assertions.html#g-print">g_print</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"it was null</span><span class="specialchar">\n</span><span class="string">"</span><span class="symbol">);</span>
 866 <span class="normal">  </span><span class="function"><a href="glib-Memory-Allocation.html#g-free">g_free</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">str</span><span class="symbol">);</span>
 867
 868
 869 <span class="normal">  </span><span class="function"><a href="glib-GVariant.html#g-variant-get">g_variant_get</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">value2</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"m&amp;s"</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">cstr</span><span class="symbol">);</span>
 870 <span class="normal">  </span><span class="keyword">if</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">cstr </span><span class="symbol">!=</span><span class="normal"> <a href="glib-Standard-Macros.html#NULL:CAPS">NULL</a></span><span class="symbol">)</span>
 871 <span class="normal">    </span><span class="function"><a href="glib-Warnings-and-Assertions.html#g-print">g_print</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"str: %s</span><span class="specialchar">\n</span><span class="string">"</span><span class="symbol">,</span><span class="normal"> cstr</span><span class="symbol">);</span>
 872 <span class="normal">  </span><span class="keyword">else</span>
 873 <span class="normal">    </span><span class="function"><a href="glib-Warnings-and-Assertions.html#g-print">g_print</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"it was null</span><span class="specialchar">\n</span><span class="string">"</span><span class="symbol">);</span>
 874 <span class="normal">  </span><span class="comment">/* don't free 'cstr' */</span>
 875
 876
 877 <span class="normal">  </span><span class="comment">/* NULL passed for the gboolean *, but two 'gint32 *' still collected */</span>
 878 <span class="normal">  </span><span class="function"><a href="glib-GVariant.html#g-variant-get">g_variant_get</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">value3</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"(m(ii)s)"</span><span class="symbol">,</span><span class="normal"> <a href="glib-Standard-Macros.html#NULL:CAPS">NULL</a></span><span class="symbol">,</span><span class="normal"> <a href="glib-Standard-Macros.html#NULL:CAPS">NULL</a></span><span class="symbol">,</span><span class="normal"> <a href="glib-Standard-Macros.html#NULL:CAPS">NULL</a></span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">str</span><span class="symbol">);</span>
 879 <span class="normal">  </span><span class="function"><a href="glib-Warnings-and-Assertions.html#g-print">g_print</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"string is %s</span><span class="specialchar">\n</span><span class="string">"</span><span class="symbol">,</span><span class="normal"> str</span><span class="symbol">);</span>
 880 <span class="normal">  </span><span class="function"><a href="glib-Memory-Allocation.html#g-free">g_free</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">str</span><span class="symbol">);</span>
 881
 882 <span class="normal">  </span><span class="comment">/* note: &amp;s used, so g_free() not needed */</span>
 883 <span class="normal">  </span><span class="function"><a href="glib-GVariant.html#g-variant-get">g_variant_get</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">value4</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"(m(ii)&amp;s)"</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">just</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">x</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">y</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">cstr</span><span class="symbol">);</span>
 884 <span class="normal">  </span><span class="keyword">if</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">just</span><span class="symbol">)</span>
 885 <span class="normal">    </span><span class="function"><a href="glib-Warnings-and-Assertions.html#g-print">g_print</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"it was (%d, %d)</span><span class="specialchar">\n</span><span class="string">"</span><span class="symbol">,</span><span class="normal"> x</span><span class="symbol">,</span><span class="normal"> y</span><span class="symbol">);</span>
 886 <span class="normal">  </span><span class="keyword">else</span>
 887 <span class="normal">    </span><span class="function"><a href="glib-Warnings-and-Assertions.html#g-print">g_print</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"it was null</span><span class="specialchar">\n</span><span class="string">"</span><span class="symbol">);</span>
 888 <span class="normal">  </span><span class="function"><a href="glib-Warnings-and-Assertions.html#g-print">g_print</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"string is %s</span><span class="specialchar">\n</span><span class="string">"</span><span class="symbol">,</span><span class="normal"> cstr</span><span class="symbol">);</span>
 889 <span class="normal">  </span><span class="comment">/* don't free 'cstr' */</span>
 890
 891
 892 <span class="normal">  </span><span class="function"><a href="glib-GVariant.html#g-variant-get">g_variant_get</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">value5</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"(m*s)"</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">contents</span><span class="symbol">,</span><span class="normal"> <a href="glib-Standard-Macros.html#NULL:CAPS">NULL</a></span><span class="symbol">);</span><span class="normal"> </span><span class="comment">/* ignore the string. */</span>
 893 <span class="normal">  </span><span class="keyword">if</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">contents </span><span class="symbol">!=</span><span class="normal"> <a href="glib-Standard-Macros.html#NULL:CAPS">NULL</a></span><span class="symbol">)</span>
 894 <span class="normal">    </span><span class="cbracket">{</span>
 895 <span class="normal">      </span><span class="function"><a href="glib-GVariant.html#g-variant-get">g_variant_get</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">contents</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"(ii)"</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">x</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">y</span><span class="symbol">);</span>
 896 <span class="normal">      </span><span class="function"><a href="glib-Warnings-and-Assertions.html#g-print">g_print</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"it was (%d, %d)</span><span class="specialchar">\n</span><span class="string">"</span><span class="symbol">,</span><span class="normal"> x</span><span class="symbol">,</span><span class="normal"> y</span><span class="symbol">);</span>
 897 <span class="normal">      </span><span class="function"><a href="glib-GVariant.html#g-variant-unref">g_variant_unref</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">contents</span><span class="symbol">);</span>
 898 <span class="normal">    </span><span class="cbracket">}</span>
 899 <span class="normal">  </span><span class="keyword">else</span>
 900 <span class="normal">    </span><span class="function"><a href="glib-Warnings-and-Assertions.html#g-print">g_print</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"it was null</span><span class="specialchar">\n</span><span class="string">"</span><span class="symbol">);</span>
 901 <span class="cbracket">}</span></pre></td>
 902       </tr>
 903     </tbody>
 904   </table>
 905 </div>
 906
 907 </div>
 908 </div>
 909 <hr>
 910 <div class="refsect2">
 911 <a name="gvariant-format-strings-tuples"></a><h3>Tuples</h3>
 912 <p>
 913     <span class="strong"><strong>
 914      Characters: <code class="code">()</code>
 915     </strong></span>
 916    </p>
 917 <p>
 918     Tuples are handled by handling each item in the tuple, in sequence.  Each item is handled in the usual way.
 919    </p>
 920 <div class="refsect3">
 921 <a name="id479172"></a><h4>Examples</h4>
 922 <div class="informalexample">
 923   <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
 924     <tbody>
 925       <tr>
 926         <td class="listing_lines" align="right"><pre>1
 927 2
 928 3
 929 4
 930 5
 931 6
 932 7
 933 8
 934 9
 935 10
 936 11
 937 12
 938 13
 939 14
 940 15</pre></td>
 941         <td class="listing_code"><pre class="programlisting"><span class="usertype">GVariant</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">value1</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">value2</span><span class="symbol">;</span>
 942
 943 <span class="normal">value1 </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new">g_variant_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"(s(ii))"</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"Hello"</span><span class="symbol">,</span><span class="normal"> </span><span class="number">55</span><span class="symbol">,</span><span class="normal"> </span><span class="number">77</span><span class="symbol">);</span>
 944 <span class="normal">value2 </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new">g_variant_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"()"</span><span class="symbol">);</span>
 945
 946 <span class="cbracket">{</span>
 947 <span class="normal">  </span><span class="usertype">gchar</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">string</span><span class="symbol">;</span>
 948 <span class="normal">  </span><span class="usertype">gint</span><span class="normal"> x</span><span class="symbol">,</span><span class="normal"> y</span><span class="symbol">;</span>
 949
 950 <span class="normal">  </span><span class="function"><a href="glib-GVariant.html#g-variant-get">g_variant_get</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">value1</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"(s(ii))"</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">string</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">x</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">y</span><span class="symbol">);</span>
 951 <span class="normal">  </span><span class="function"><a href="glib-Warnings-and-Assertions.html#g-print">g_print</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"%s, %d, %d</span><span class="specialchar">\n</span><span class="string">"</span><span class="symbol">,</span><span class="normal"> string</span><span class="symbol">,</span><span class="normal"> x</span><span class="symbol">,</span><span class="normal"> y</span><span class="symbol">);</span>
 952 <span class="normal">  </span><span class="function"><a href="glib-Memory-Allocation.html#g-free">g_free</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">string</span><span class="symbol">);</span>
 953
 954 <span class="normal">  </span><span class="function"><a href="glib-GVariant.html#g-variant-get">g_variant_get</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">value2</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"()"</span><span class="symbol">);</span><span class="normal">   </span><span class="comment">/* do nothing... */</span>
 955 <span class="cbracket">}</span></pre></td>
 956       </tr>
 957     </tbody>
 958   </table>
 959 </div>
 960
 961 </div>
 962 </div>
 963 <hr>
 964 <div class="refsect2">
 965 <a name="gvariant-format-strings-dictionaries"></a><h3>Dictionaries</h3>
 966 <p>
 967     <span class="strong"><strong>
 968      Characters: <code class="code">{}</code>
 969     </strong></span>
 970    </p>
 971 <p>
 972     Dictionary entries are handled by handling first the key, then the value.  Each is handled in the usual way.
 973    </p>
 974 <div class="refsect3">
 975 <a name="id480074"></a><h4>Examples</h4>
 976 <div class="informalexample">
 977   <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
 978     <tbody>
 979       <tr>
 980         <td class="listing_lines" align="right"><pre>1
 981 2
 982 3
 983 4
 984 5
 985 6
 986 7</pre></td>
 987         <td class="listing_code"><pre class="programlisting"><span class="usertype">GVariantBuilder</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">b</span><span class="symbol">;</span>
 988 <span class="usertype">GVariant</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">dict</span><span class="symbol">;</span>
 989
 990 <span class="normal">b </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-builder-new">g_variant_builder_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="function"><a href="glib-GVariantType.html#G-VARIANT-TYPE:CAPS">G_VARIANT_TYPE</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"a{sv}"</span><span class="symbol">));</span>
 991 <span class="function"><a href="glib-GVariant.html#g-variant-builder-add">g_variant_builder_add</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">b</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"{sv}"</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"name"</span><span class="symbol">,</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new-string">g_variant_new_string</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"foo"</span><span class="symbol">));</span>
 992 <span class="function"><a href="glib-GVariant.html#g-variant-builder-add">g_variant_builder_add</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">b</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"{sv}"</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"timeout"</span><span class="symbol">,</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new-int32">g_variant_new_int32</a></span><span class="normal"> </span><span class="symbol">(</span><span class="number">10</span><span class="symbol">));</span>
 993 <span class="normal">dict </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-builder-end">g_variant_builder_end</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">b</span><span class="symbol">);</span></pre></td>
 994       </tr>
 995     </tbody>
 996   </table>
 997 </div>
 998
 999 </div>
1000 </div>
1001 <hr>
1002 <div class="refsect2">
1003 <a name="gvariant-format-strings-gvariant"></a><h3>GVariant *</h3>
1004 <p>
1005     <span class="strong"><strong>
1006      Characters: <code class="literal">@</code>, <code class="literal">*</code>, <code class="literal">?</code>, <code class="literal">r</code>
1007     </strong></span>
1008
1009    </p>
1010 <p>
1011     Upon encountering a '<code class="literal">@</code>' in front of a type string,
1012     <a class="link" href="glib-GVariant.html#g-variant-new" title="g_variant_new ()"><code class="function">g_variant_new()</code></a> takes a
1013     non-<a class="link" href="glib-Standard-Macros.html#NULL:CAPS" title="NULL"><code class="literal">NULL</code></a> pointer to a
1014     <a class="link" href="glib-GVariant.html#GVariant" title="GVariant"><span class="type">GVariant</span></a> and uses its value directly instead of collecting arguments to
1015     create the value.  The provided <a class="link" href="glib-GVariant.html#GVariant" title="GVariant"><span class="type">GVariant</span></a> must have a type that matches the
1016     type string following the '<code class="literal">@</code>'.  '<code class="literal">*</code>' is
1017     the same as '<code class="literal">@*</code>' (ie: take a <a class="link" href="glib-GVariant.html#GVariant" title="GVariant"><span class="type">GVariant</span></a> of any type).
1018     '<code class="literal">?</code>' is the same as '<code class="literal">@?</code>' (ie: take a
1019     <a class="link" href="glib-GVariant.html#GVariant" title="GVariant"><span class="type">GVariant</span></a> of any basic type).  '<code class="literal">r</code>' is the same as
1020     '<code class="literal">@r</code>' (ie: take a <a class="link" href="glib-GVariant.html#GVariant" title="GVariant"><span class="type">GVariant</span></a> of any tuple type).
1021    </p>
1022 <p>
1023     Upon encountering a '<code class="literal">@</code>' in front of a type string,
1024     <a class="link" href="glib-GVariant.html#g-variant-get" title="g_variant_get ()"><code class="function">g_variant_get()</code></a>
1025     takes a pointer to a <code class="code">(<a class="link" href="glib-GVariant.html#GVariant" title="GVariant">GVariant</a> *)</code> (ie: a
1026     <code class="code">(<a class="link" href="glib-GVariant.html#GVariant" title="GVariant">GVariant</a> **)</code>) and sets it to a new reference to a
1027     <a class="link" href="glib-GVariant.html#GVariant" title="GVariant"><span class="type">GVariant</span></a> containing the value (instead of deconstructing the value into
1028     C types in the usual way).  <a class="link" href="glib-Standard-Macros.html#NULL:CAPS" title="NULL"><code class="literal">NULL</code></a> can be given to ignore the
1029     value.  '<code class="literal">*</code>', '<code class="literal">?</code>' and '<code class="literal">r</code>' are handled in a way analogous to
1030     what is stated above.
1031    </p>
1032 <p>
1033     You can always use '<code class="literal">*</code>' as an alternative to '<code class="literal">?</code>', '<code class="literal">r</code>' or any
1034     use of '<code class="literal">@</code>'.  Using the other characters where possible is recommended, however, due to the
1035     improvements in type safety and code self-documentation.
1036    </p>
1037 <div class="refsect3">
1038 <a name="id459182"></a><h4>Examples</h4>
1039 <div class="informalexample">
1040   <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
1041     <tbody>
1042       <tr>
1043         <td class="listing_lines" align="right"><pre>1
1044 2
1045 3
1046 4
1047 5
1048 6
1049 7
1050 8
1051 9
1052 10
1053 11
1054 12
1055 13
1056 14
1057 15
1058 16
1059 17
1060 18
1061 19
1062 20
1063 21
1064 22
1065 23</pre></td>
1066         <td class="listing_code"><pre class="programlisting"><span class="usertype">GVariant</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">value1</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">value2</span><span class="symbol">;</span>
1067
1068 <span class="normal">value1 </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new">g_variant_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"(i@ii)"</span><span class="symbol">,</span><span class="normal"> </span><span class="number">44</span><span class="symbol">,</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new-int32">g_variant_new_int32</a></span><span class="normal"> </span><span class="symbol">(</span><span class="number">55</span><span class="symbol">),</span><span class="normal"> </span><span class="number">66</span><span class="symbol">);</span>
1069
1070 <span class="comment">/* note: consumes floating reference count on 'value1' */</span>
1071 <span class="normal">value2 </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new">g_variant_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"(@(iii)*)"</span><span class="symbol">,</span><span class="normal"> value1</span><span class="symbol">,</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new-string">g_variant_new_string</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"foo"</span><span class="symbol">));</span>
1072
1073 <span class="cbracket">{</span>
1074 <span class="normal">  </span><span class="keyword">const</span><span class="normal"> </span><span class="usertype">gchar</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">string</span><span class="symbol">;</span>
1075 <span class="normal">  </span><span class="usertype">GVariant</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">tmp</span><span class="symbol">;</span>
1076 <span class="normal">  </span><span class="usertype">gsize</span><span class="normal"> length</span><span class="symbol">;</span>
1077 <span class="normal">  </span><span class="usertype">gint</span><span class="normal"> x</span><span class="symbol">,</span><span class="normal"> y</span><span class="symbol">,</span><span class="normal"> z</span><span class="symbol">;</span>
1078
1079 <span class="normal">  </span><span class="function"><a href="glib-GVariant.html#g-variant-get">g_variant_get</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">value2</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"((iii)*)"</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">x</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">y</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">z</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">tmp</span><span class="symbol">);</span>
1080 <span class="normal">  string </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-get-string">g_variant_get_string</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">tmp</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">length</span><span class="symbol">);</span>
1081 <span class="normal">  </span><span class="function"><a href="glib-Warnings-and-Assertions.html#g-print">g_print</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"it is %d %d %d %s (length=%d)</span><span class="specialchar">\n</span><span class="string">"</span><span class="symbol">,</span><span class="normal"> x</span><span class="symbol">,</span><span class="normal"> y</span><span class="symbol">,</span><span class="normal"> z</span><span class="symbol">,</span><span class="normal"> string</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">(</span><span class="type">int</span><span class="symbol">)</span><span class="normal"> length</span><span class="symbol">);</span>
1082 <span class="normal">  </span><span class="function"><a href="glib-GVariant.html#g-variant-unref">g_variant_unref</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">tmp</span><span class="symbol">);</span>
1083
1084 <span class="normal">  </span><span class="comment">/* quick way to skip all the values in a tuple */</span>
1085 <span class="normal">  </span><span class="function"><a href="glib-GVariant.html#g-variant-get">g_variant_get</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">value2</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"(rs)"</span><span class="symbol">,</span><span class="normal"> <a href="glib-Standard-Macros.html#NULL:CAPS">NULL</a></span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">string</span><span class="symbol">);</span><span class="normal"> </span><span class="comment">/* or "(@(iii)s)" */</span>
1086 <span class="normal">  </span><span class="function"><a href="glib-Warnings-and-Assertions.html#g-print">g_print</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"i only got the string: %s</span><span class="specialchar">\n</span><span class="string">"</span><span class="symbol">,</span><span class="normal"> string</span><span class="symbol">);</span>
1087 <span class="normal">  </span><span class="function"><a href="glib-Memory-Allocation.html#g-free">g_free</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">string</span><span class="symbol">);</span>
1088 <span class="cbracket">}</span></pre></td>
1089       </tr>
1090     </tbody>
1091   </table>
1092 </div>
1093
1094 </div>
1095 </div>
1096 <hr>
1097 <div class="refsect2">
1098 <a name="gvariant-format-strings-pointers"></a><h3>Pointers</h3>
1099 <p>
1100     <span class="strong"><strong>
1101      Characters: <code class="code">&amp;</code>
1102     </strong></span>
1103    </p>
1104 <p>
1105     The '<code class="code">&amp;</code>' character is used to indicate that serialised data should be directly exchanged via a
1106     pointer.
1107    </p>
1108 <p>
1109     Currently, the only use for this character is when it is applied to a string (ie: '<code class="literal">&amp;s</code>',
1110     '<code class="literal">&amp;o</code>' or '<code class="code">&amp;g</code>').  For
1111     <a class="link" href="glib-GVariant.html#g-variant-new" title="g_variant_new ()"><code class="function">g_variant_new()</code></a> this has absolutely no effect.  The string
1112     is collected and duplicated normally.  For <a class="link" href="glib-GVariant.html#g-variant-get" title="g_variant_get ()"><code class="function">g_variant_get()</code></a>
1113     it means that instead of creating a newly allocated copy of the string, a pointer to the serialised data is
1114     returned.  This pointer should not be freed.  Validity checks are performed to ensure that the string data will
1115     always be properly nul-terminated.
1116    </p>
1117 <div class="refsect3">
1118 <a name="id572841"></a><h4>Examples</h4>
1119 <div class="informalexample">
1120   <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
1121     <tbody>
1122       <tr>
1123         <td class="listing_lines" align="right"><pre>1
1124 2
1125 3
1126 4
1127 5
1128 6
1129 7
1130 8
1131 9</pre></td>
1132         <td class="listing_code"><pre class="programlisting"><span class="cbracket">{</span>
1133 <span class="normal">  </span><span class="keyword">const</span><span class="normal"> </span><span class="usertype">gchar</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">str</span><span class="symbol">;</span>
1134 <span class="normal">  </span><span class="usertype">GVariant</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">value</span><span class="symbol">;</span>
1135
1136 <span class="normal">  value </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-new">g_variant_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"&amp;s"</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"hello world"</span><span class="symbol">);</span>
1137 <span class="normal">  str </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="glib-GVariant.html#g-variant-get">g_variant_get</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"&amp;s"</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&amp;</span><span class="normal">str</span><span class="symbol">);</span>
1138 <span class="normal">  </span><span class="function"><a href="glib-Warnings-and-Assertions.html#g-print">g_print</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"string is: %s</span><span class="specialchar">\n</span><span class="string">"</span><span class="symbol">,</span><span class="normal"> str</span><span class="symbol">);</span>
1139 <span class="normal">  </span><span class="comment">/* no need to free str */</span>
1140 <span class="cbracket">}</span></pre></td>
1141       </tr>
1142     </tbody>
1143   </table>
1144 </div>
1145
1146 </div>
1147 </div>
1148 <hr>
1149 <div class="refsect2">
1150 <a name="gvariant-format-strings-convenience"></a><h3>Convenience Conversions</h3>
1151 <p>
1152     <span class="strong"><strong>
1153      Characters: <code class="literal">^</code>
1154     </strong></span>
1155    </p>
1156 <p>
1157     The '<code class="literal">^</code>' character currently supports conversion to and from bytestrings or to and from arrays
1158     of strings or bytestrings.  It has a number of forms.
1159    </p>
1160 <p>
1161     In all forms, when used with <a class="link" href="glib-GVariant.html#g-variant-new" title="g_variant_new ()"><code class="function">g_variant_new()</code></a> one
1162     pointer value is collected from the variable arguments and passed to a function (as given in the table below).
1163     The result of that function is used as the value for this position.  When used with
1164     <a class="link" href="glib-GVariant.html#g-variant-get" title="g_variant_get ()"><code class="function">g_variant_get()</code></a> one pointer value is produced by using
1165     the function (given in the table) and returned by reference.
1166    </p>
1167 <div class="informaltable"><table border="1">
1168 <colgroup>
1169 <col class="col_0">
1170 <col class="col_1">
1171 </colgroup>
1172 <tbody>
1173 <tr>
1174 <td>
1175         <p>
1176          <span class="strong"><strong>Conversion</strong></span>
1177         </p>
1178        </td>
1179 <td>
1180         <p>
1181           <span class="strong"><strong>
1182             Used with <a class="link" href="glib-GVariant.html#g-variant-new" title="g_variant_new ()"><code class="function">g_variant_new()</code></a>
1183           </strong></span>
1184         </p>
1185        </td>
1186 <td>
1187         <p>
1188           <span class="strong"><strong>
1189             Used with <a class="link" href="glib-GVariant.html#g-variant-get" title="g_variant_get ()"><code class="function">g_variant_get()</code></a>
1190           </strong></span>
1191         </p>
1192        </td>
1193 </tr>
1194 <tr>
1195 <td>
1196         <p>
1197          <span class="strong"><strong>
1198           <code class="literal">^as</code>
1199          </strong></span>
1200         </p>
1201        </td>
1202 <td rowspan="2">
1203         <p>
1204          equivalent to <a class="link" href="glib-GVariant.html#g-variant-new-strv" title="g_variant_new_strv ()"><code class="function">g_variant_new_strv()</code></a>
1205         </p>
1206        </td>
1207 <td>
1208         <p>
1209          equivalent to <a class="link" href="glib-GVariant.html#g-variant-dup-strv" title="g_variant_dup_strv ()"><code class="function">g_variant_dup_strv()</code></a>
1210         </p>
1211        </td>
1212 </tr>
1213 <tr>
1214 <td>
1215         <p>
1216          <span class="strong"><strong>
1217           <code class="literal">^a&amp;s</code>
1218          </strong></span>
1219         </p>
1220        </td>
1221 <td>
1222         <p>
1223          equivalent to <a class="link" href="glib-GVariant.html#g-variant-get-strv" title="g_variant_get_strv ()"><code class="function">g_variant_get_strv()</code></a>
1224         </p>
1225        </td>
1226 </tr>
1227 <tr>
1228 <td>
1229         <p>
1230          <span class="strong"><strong>
1231           <code class="literal">^ao</code>
1232          </strong></span>
1233         </p>
1234        </td>
1235 <td rowspan="2">
1236         <p>
1237          equivalent to <a class="link" href="glib-GVariant.html#g-variant-new-objv" title="g_variant_new_objv ()"><code class="function">g_variant_new_objv()</code></a>
1238         </p>
1239        </td>
1240 <td>
1241         <p>
1242          equivalent to <a class="link" href="glib-GVariant.html#g-variant-dup-objv" title="g_variant_dup_objv ()"><code class="function">g_variant_dup_objv()</code></a>
1243         </p>
1244        </td>
1245 </tr>
1246 <tr>
1247 <td>
1248         <p>
1249          <span class="strong"><strong>
1250           <code class="literal">^a&amp;o</code>
1251          </strong></span>
1252         </p>
1253        </td>
1254 <td>
1255         <p>
1256          equivalent to <a class="link" href="glib-GVariant.html#g-variant-get-objv" title="g_variant_get_objv ()"><code class="function">g_variant_get_objv()</code></a>
1257         </p>
1258        </td>
1259 </tr>
1260 <tr>
1261 <td>
1262         <p>
1263          <span class="strong"><strong>
1264           <code class="literal">^ay</code>
1265          </strong></span>
1266         </p>
1267        </td>
1268 <td rowspan="2">
1269         <p>
1270          equivalent to <a class="link" href="glib-GVariant.html#g-variant-new-bytestring" title="g_variant_new_bytestring ()"><code class="function">g_variant_new_bytestring()</code></a>
1271         </p>
1272        </td>
1273 <td>
1274         <p>
1275          equivalent to <a class="link" href="glib-GVariant.html#g-variant-dup-bytestring" title="g_variant_dup_bytestring ()"><code class="function">g_variant_dup_bytestring()</code></a>
1276         </p>
1277        </td>
1278 </tr>
1279 <tr>
1280 <td>
1281         <p>
1282          <span class="strong"><strong>
1283           <code class="literal">^&amp;ay</code>
1284          </strong></span>
1285         </p>
1286        </td>
1287 <td>
1288         <p>
1289          equivalent to <a class="link" href="glib-GVariant.html#g-variant-get-bytestring" title="g_variant_get_bytestring ()"><code class="function">g_variant_get_bytestring()</code></a>
1290         </p>
1291        </td>
1292 </tr>
1293 <tr>
1294 <td>
1295         <p>
1296          <span class="strong"><strong>
1297           <code class="literal">^aay</code>
1298          </strong></span>
1299         </p>
1300        </td>
1301 <td rowspan="2">
1302         <p>
1303          equivalent to <a class="link" href="glib-GVariant.html#g-variant-new-bytestring-array" title="g_variant_new_bytestring_array ()"><code class="function">g_variant_new_bytestring_array()</code></a>
1304         </p>
1305        </td>
1306 <td>
1307         <p>
1308          equivalent to <a class="link" href="glib-GVariant.html#g-variant-dup-bytestring-array" title="g_variant_dup_bytestring_array ()"><code class="function">g_variant_dup_bytestring_array()</code></a>
1309         </p>
1310        </td>
1311 </tr>
1312 <tr>
1313 <td>
1314         <p>
1315          <span class="strong"><strong>
1316           <code class="literal">^a&amp;ay</code>
1317          </strong></span>
1318         </p>
1319        </td>
1320 <td>
1321         <p>
1322          equivalent to <a class="link" href="glib-GVariant.html#g-variant-get-bytestring-array" title="g_variant_get_bytestring_array ()"><code class="function">g_variant_get_bytestring_array()</code></a>
1323         </p>
1324        </td>
1325 </tr>
1326 </tbody>
1327 </table></div>
1328 </div>
1329 </div>
1330 </div>
1331 <div class="footer">
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