~ubuntu-branches/ubuntu/utopic/glib2.0/utopic

<a href="gobject-Standard-Parameter-and-Value-Types.html#g-value-set-static-string">g_value_set_static_string</a> (dest_value, "An important number");

305

else

306

307

}

308

309

int

310

main (int argc,

311

char *argv[])

312

{

313

// GValues must be initialized

314

GValue a = <a href="gobject-Generic-values.html#G-VALUE-INIT:CAPS">G_VALUE_INIT</a>;

315

GValue b = <a href="gobject-Generic-values.html#G-VALUE-INIT:CAPS">G_VALUE_INIT</a>;

316

const gchar *message;

317

318

// The GValue starts empty

319

<a href="http://library.gnome.org/devel/glib/unstable/glib-Testing.html#g-assert">g_assert</a> (!<a href="gobject-Standard-Parameter-and-Value-Types.html#G-VALUE-HOLDS-STRING:CAPS">G_VALUE_HOLDS_STRING</a> (&a));

320

321

// Put a string in it

322

<a href="gobject-Generic-values.html#g-value-init">g_value_init</a> (&a, <a href="gobject-Type-Information.html#G-TYPE-STRING:CAPS">G_TYPE_STRING</a>);

323

<a href="http://library.gnome.org/devel/glib/unstable/glib-Testing.html#g-assert">g_assert</a> (<a href="gobject-Standard-Parameter-and-Value-Types.html#G-VALUE-HOLDS-STRING:CAPS">G_VALUE_HOLDS_STRING</a> (&a));

324

<a href="gobject-Standard-Parameter-and-Value-Types.html#g-value-set-static-string">g_value_set_static_string</a> (&a, "Hello, world!");

325

<a href="http://library.gnome.org/devel/glib/unstable/glib-String-Utility-Functions.html#g-printf">g_printf</a> ("%s\n", <a href="gobject-Standard-Parameter-and-Value-Types.html#g-value-get-string">g_value_get_string</a> (&a));

326

327

// Reset it to its pristine state

328

<a href="gobject-Generic-values.html#g-value-unset">g_value_unset</a> (&a);

329

330

// It can then be reused for another type

331

<a href="gobject-Generic-values.html#g-value-init">g_value_init</a> (&a, <a href="gobject-Type-Information.html#G-TYPE-INT:CAPS">G_TYPE_INT</a>);

332

<a href="gobject-Standard-Parameter-and-Value-Types.html#g-value-set-int">g_value_set_int</a> (&a, 42);

333

334

// Attempt to transform it into a GValue of type STRING

335

<a href="gobject-Generic-values.html#g-value-init">g_value_init</a> (&b, <a href="gobject-Type-Information.html#G-TYPE-STRING:CAPS">G_TYPE_STRING</a>);

336

337

// An INT is transformable to a STRING

338

<a href="http://library.gnome.org/devel/glib/unstable/glib-Testing.html#g-assert">g_assert</a> (<a href="gobject-Generic-values.html#g-value-type-transformable">g_value_type_transformable</a> (<a href="gobject-Type-Information.html#G-TYPE-INT:CAPS">G_TYPE_INT</a>, <a href="gobject-Type-Information.html#G-TYPE-STRING:CAPS">G_TYPE_STRING</a>));

339

340

<a href="gobject-Generic-values.html#g-value-transform">g_value_transform</a> (&a, &b);

341

342

343

// Attempt to transform it again using a custom transform function

344

<a href="gobject-Generic-values.html#g-value-register-transform-func">g_value_register_transform_func</a> (<a href="gobject-Type-Information.html#G-TYPE-INT:CAPS">G_TYPE_INT</a>, <a href="gobject-Type-Information.html#G-TYPE-STRING:CAPS">G_TYPE_STRING</a>, int2string);

345

346

347

return 0;

348

}</pre></td>

297

<td class="listing_code"><pre class="programlisting">#include <glib-object.h>

298

299

static void

300

int2string (const GValue *src_value,

301

GValue *dest_value)

302

{

303

if (<a href="gobject-Standard-Parameter-and-Value-Types.html#g-value-get-int">g_value_get_int</a> (src_value) == 42)

304

<a href="gobject-Standard-Parameter-and-Value-Types.html#g-value-set-static-string">g_value_set_static_string</a> (dest_value, "An important number");

305

else

306

<a href="gobject-Standard-Parameter-and-Value-Types.html#g-value-set-static-string">g_value_set_static_string</a> (dest_value, "What's that?");

307

}

308

309

int

310

main (int argc,

311

char *argv[])

312

{

313

// GValues must be initialized

314

GValue a = G_VALUE_INIT;

315

GValue b = G_VALUE_INIT;

316

const gchar *message;

317

318

// The GValue starts empty

319

<a href="../glib/glib-Testing.html#g-assert">g_assert</a> (!<a href="gobject-Standard-Parameter-and-Value-Types.html#G-VALUE-HOLDS-STRING:CAPS">G_VALUE_HOLDS_STRING</a> (&a));

320

321

// Put a string in it

322

<a href="gobject-Generic-values.html#g-value-init">g_value_init</a> (&a, G_TYPE_STRING);

323

<a href="../glib/glib-Testing.html#g-assert">g_assert</a> (<a href="gobject-Standard-Parameter-and-Value-Types.html#G-VALUE-HOLDS-STRING:CAPS">G_VALUE_HOLDS_STRING</a> (&a));

324

<a href="gobject-Standard-Parameter-and-Value-Types.html#g-value-set-static-string">g_value_set_static_string</a> (&a, "Hello, world!");

325

<a href="../glib/glib-String-Utility-Functions.html#g-printf">g_printf</a> ("%s\n", <a href="gobject-Standard-Parameter-and-Value-Types.html#g-value-get-string">g_value_get_string</a> (&a));

326

327

// Reset it to its pristine state

328

<a href="gobject-Generic-values.html#g-value-unset">g_value_unset</a> (&a);

329

330

// It can then be reused for another type

331

332

<a href="gobject-Standard-Parameter-and-Value-Types.html#g-value-set-int">g_value_set_int</a> (&a, 42);

333

334

// Attempt to transform it into a GValue of type STRING

335

<a href="gobject-Generic-values.html#g-value-init">g_value_init</a> (&b, G_TYPE_STRING);

336

337

// An INT is transformable to a STRING

338

<a href="../glib/glib-Testing.html#g-assert">g_assert</a> (<a href="gobject-Generic-values.html#g-value-type-transformable">g_value_type_transformable</a> (G_TYPE_INT, G_TYPE_STRING));

339

340

<a href="gobject-Generic-values.html#g-value-transform">g_value_transform</a> (&a, &b);

341

342

343

// Attempt to transform it again using a custom transform function

344

<a href="gobject-Generic-values.html#g-value-register-transform-func">g_value_register_transform_func</a> (G_TYPE_INT, G_TYPE_STRING, int2string);

345

346

347

return 0;

348

}</pre></td>

349

</tr>

350

</tbody>

351

</table>

363

holds (or contains) a value of <code>type</code>

364

365

This macro will also check for <code>value</code>

366

!= <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> and issue a

366

!= <a href="../glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> and issue a

367

warning if the check fails.

368

369

<a name="id-1.4.8.7.2.5"></a><h4>Parameters</h4>

389

</div>

390

391

<a name="id-1.4.8.7.2.6"></a><h4>Returns</h4>

392

<a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if <code>value</code>

392

<a href="../glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if <code>value</code>

393

holds the <code>type</code>

394

.

395

507

</div>

508

509

<a name="id-1.4.8.7.6.6"></a><h4>Returns</h4>

510

<a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> on success

510

<a href="../glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> on success

511

512

</div>

513

</div>

535

</div>

536

537

<a name="id-1.4.8.7.7.6"></a><h4>Returns</h4>

538

<a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> on success.

538

<a href="../glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> on success.

539

540

</div>

541

</div>

554

</pre>

555

556

<code class="literal">G_TYPE_VALUE_ARRAY</code> has been deprecated since version 2.32 and should not be used in newly-written code.

557

Use <a href="http://library.gnome.org/devel/glib/unstable/glib-Arrays.html#GArray">GArray</a> instead of <a class="link" href="gobject-Value-arrays.html#GValueArray" title="struct GValueArray">GValueArray</a>

557

Use <a href="../glib/glib-Arrays.html#GArray">GArray</a> instead of <a class="link" href="gobject-Value-arrays.html#GValueArray" title="struct GValueArray">GValueArray</a>

558

</div>

559

The type ID of the "GValueArray" type which is a boxed type,

560

used to pass around pointers to GValueArrays.

689

<a name="g-value-init-from-instance"></a><h3>g_value_init_from_instance ()</h3>

690

<pre class="programlisting">void

691

g_value_init_from_instance (<code><a class="link" href="gobject-Generic-values.html#GValue" title="GValue">GValue</a> *value</code>,

692

<code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer">gpointer</a> instance</code>);</pre>

692

<code><a href="../glib/glib-Basic-Types.html#gpointer">gpointer</a> instance</code>);</pre>

693

Initializes and sets <code>value</code>

694

from an instantiatable type via the

695

value_table's <code class="function">collect_value()</code> function.

729

<a name="g-value-set-instance"></a><h3>g_value_set_instance ()</h3>

730

<pre class="programlisting">void

731

g_value_set_instance (<code><a class="link" href="gobject-Generic-values.html#GValue" title="GValue">GValue</a> *value</code>,

732

<code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer">gpointer</a> instance</code>);</pre>

732

<code><a href="../glib/glib-Basic-Types.html#gpointer">gpointer</a> instance</code>);</pre>

733

Sets <code>value</code>

734

from an instantiatable type via the

735

value_table's <code class="function">collect_value()</code> function.

759

<hr>

760

761

<a name="g-value-fits-pointer"></a><h3>g_value_fits_pointer ()</h3>

762

<pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean">gboolean</a>

762

<pre class="programlisting"><a href="../glib/glib-Basic-Types.html#gboolean">gboolean</a>

763

g_value_fits_pointer (<code>const <a class="link" href="gobject-Generic-values.html#GValue" title="GValue">GValue</a> *value</code>);</pre>

764

Determines if <code>value</code>

765

will fit inside the size of a pointer value.

781

</div>

782

783

<a name="id-1.4.8.7.16.6"></a><h4>Returns</h4>

784

<a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if <code>value</code>

784

<a href="../glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if <code>value</code>

785

will fit inside a pointer value.

786

787

</div>

789

<hr>

790

791

<a name="g-value-peek-pointer"></a><h3>g_value_peek_pointer ()</h3>

792

<pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer">gpointer</a>

792

<pre class="programlisting"><a href="../glib/glib-Basic-Types.html#gpointer">gpointer</a>

793

g_value_peek_pointer (<code>const <a class="link" href="gobject-Generic-values.html#GValue" title="GValue">GValue</a> *value</code>);</pre>

794

Returns the value contents as pointer. This function asserts that

795

<a class="link" href="gobject-Generic-values.html#g-value-fits-pointer" title="g_value_fits_pointer ()"><code class="function">g_value_fits_pointer()</code></a> returned <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> for the passed in value.

795

<a class="link" href="gobject-Generic-values.html#g-value-fits-pointer" title="g_value_fits_pointer ()"><code class="function">g_value_fits_pointer()</code></a> returned <a href="../glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> for the passed in value.

796

This is an internal function introduced mainly for C marshallers.

797

798

<a name="id-1.4.8.7.17.5"></a><h4>Parameters</h4>

818

<hr>

819

820

<a name="g-value-type-compatible"></a><h3>g_value_type_compatible ()</h3>

821

<pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean">gboolean</a>

821

<pre class="programlisting"><a href="../glib/glib-Basic-Types.html#gboolean">gboolean</a>

822

g_value_type_compatible (<code><a class="link" href="gobject-Type-Information.html#GType" title="GType">GType</a> src_type</code>,

823

<code><a class="link" href="gobject-Type-Information.html#GType" title="GType">GType</a> dest_type</code>);</pre>

824

Returns whether a <a class="link" href="gobject-Generic-values.html#GValue" title="GValue">GValue</a> of type <code>src_type</code>

849

</div>

850

851

<a name="id-1.4.8.7.18.6"></a><h4>Returns</h4>

852

<a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if <a class="link" href="gobject-Generic-values.html#g-value-copy" title="g_value_copy ()"><code class="function">g_value_copy()</code></a> is possible with <code>src_type</code>

852

<a href="../glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if <a class="link" href="gobject-Generic-values.html#g-value-copy" title="g_value_copy ()"><code class="function">g_value_copy()</code></a> is possible with <code>src_type</code>

853

and <code>dest_type</code>

854

.

855

858

<hr>

859

860

<a name="g-value-type-transformable"></a><h3>g_value_type_transformable ()</h3>

861

<pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean">gboolean</a>

861

<pre class="programlisting"><a href="../glib/glib-Basic-Types.html#gboolean">gboolean</a>

862

g_value_type_transformable (<code><a class="link" href="gobject-Type-Information.html#GType" title="GType">GType</a> src_type</code>,

863

<code><a class="link" href="gobject-Type-Information.html#GType" title="GType">GType</a> dest_type</code>);</pre>

864

Check whether <a class="link" href="gobject-Generic-values.html#g-value-transform" title="g_value_transform ()"><code class="function">g_value_transform()</code></a> is able to transform values

891

</div>

892

893

<a name="id-1.4.8.7.19.6"></a><h4>Returns</h4>

894

<a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if the transformation is possible, <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> otherwise.

894

<a href="../glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if the transformation is possible, <a href="../glib/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> otherwise.

895

896

</div>

897

</div>

898

<hr>

899

900

<a name="g-value-transform"></a><h3>g_value_transform ()</h3>

901

<pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean">gboolean</a>

901

<pre class="programlisting"><a href="../glib/glib-Basic-Types.html#gboolean">gboolean</a>

902

g_value_transform (<code>const <a class="link" href="gobject-Generic-values.html#GValue" title="GValue">GValue</a> *src_value</code>,

903

<code><a class="link" href="gobject-Generic-values.html#GValue" title="GValue">GValue</a> *dest_value</code>);</pre>

904

Tries to cast the contents of <code>src_value</code>

1016

<hr>

1017

1018

<a name="g-strdup-value-contents"></a><h3>g_strdup_value_contents ()</h3>

1019

<pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gchar">gchar</a> *

1019

<pre class="programlisting"><a href="../glib/glib-Basic-Types.html#gchar">gchar</a> *

1020

g_strdup_value_contents (<code>const <a class="link" href="gobject-Generic-values.html#GValue" title="GValue">GValue</a> *value</code>);</pre>

1021

Return a newly allocated string, which describes the contents of a

1022

<a class="link" href="gobject-Generic-values.html#GValue" title="GValue">GValue</a>. The main purpose of this function is to describe <a class="link" href="gobject-Generic-values.html#GValue" title="GValue">GValue</a>

1058

<tbody>

1059

<tr>

1060

1061

<td class="listing_code"><pre class="programlisting">GValue value = <a href="gobject-Generic-values.html#G-VALUE-INIT:CAPS">G_VALUE_INIT</a>;</pre></td>

1061

<td class="listing_code"><pre class="programlisting">GValue value = G_VALUE_INIT;</pre></td>

1062

</tr>

1063

</tbody>

1064

</table>

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