~ubuntu-branches/debian/jessie/glib2.0/jessie

<a class="link" href="GCancellable.html#g-cancellable-set-error-if-cancelled" title="g_cancellable_set_error_if_cancelled ()">g_cancellable_set_error_if_cancelled</a> ()

</tr>

<tr>

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

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

</td>

<a class="link" href="GCancellable.html#g-cancellable-make-pollfd" title="g_cancellable_make_pollfd ()">g_cancellable_make_pollfd</a> ()

</tr>

<tr>

<a href="http://library.gnome.org/devel/glib/unstable/glib-The-Main-Event-Loop.html#GSource">GSource</a> *

<a href="../glib/glib-The-Main-Event-Loop.html#GSource">GSource</a> *

</td>

<a class="link" href="GCancellable.html#g-cancellable-source-new" title="g_cancellable_source_new ()">g_cancellable_source_new</a> ()

</tr>

100

<tr>

101

102

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

102

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

103

</td>

104

105

(<a class="link" href="GCancellable.html#GCancellableSourceFunc" title="GCancellableSourceFunc ()">*GCancellableSourceFunc</a>) ()

139

</tr>

140

<tr>

141

142

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

142

<a href="../glib/glib-Basic-Types.html#gulong">gulong</a>

143

</td>

144

145

<a class="link" href="GCancellable.html#g-cancellable-connect" title="g_cancellable_connect ()">g_cancellable_connect</a> ()

194

</div>

195

196

<a name="GCancellable.object-hierarchy"></a><h2>Object Hierarchy</h2>

197

<pre class="screen"> <a href="http://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#GObject">GObject</a>

197

<pre class="screen"> <a href="../gobject/gobject-The-Base-Object-Type.html#GObject">GObject</a>

198

╰── GCancellable

199

</pre>

200

</div>

230

<hr>

231

232

<a name="g-cancellable-is-cancelled"></a><h3>g_cancellable_is_cancelled ()</h3>

233

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

233

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

234

g_cancellable_is_cancelled (<code><a class="link" href="GCancellable.html" title="GCancellable">GCancellable</a> *cancellable</code>);</pre>

235

Checks if a cancellable job has been cancelled.

236

243

</colgroup>

244

245

<td class="parameter_name">cancellable</td>

246

<td class="parameter_description"> a <a class="link" href="GCancellable.html" title="GCancellable">GCancellable</a> or <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>. </td>

246

<td class="parameter_description"> a <a class="link" href="GCancellable.html" title="GCancellable">GCancellable</a> or <a href="../glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>. </td>

247

<td class="parameter_annotations">[<acronym title="NULL is OK, both for passing and for returning.">allow-none</acronym>]</td>

248

</tr></tbody>

249

</table></div>

250

</div>

251

252

<a name="id-1.4.5.2.9.3.6"></a><h4>Returns</h4>

253

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

253

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

254

is cancelled,

255

FALSE if called with <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> or if item is not cancelled.

255

FALSE if called with <a href="../glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> or if item is not cancelled.

256

257

</div>

258

</div>

259

<hr>

260

261

<a name="g-cancellable-set-error-if-cancelled"></a><h3>g_cancellable_set_error_if_cancelled ()</h3>

262

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

262

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

263

g_cancellable_set_error_if_cancelled (<code><a class="link" href="GCancellable.html" title="GCancellable">GCancellable</a> *cancellable</code>,

264

<code><a href="http://library.gnome.org/devel/glib/unstable/glib-Error-Reporting.html#GError">GError</a> **error</code>);</pre>

264

<code><a href="../glib/glib-Error-Reporting.html#GError">GError</a> **error</code>);</pre>

265

If the <code>cancellable</code>

266

is cancelled, sets the error to notify

267

that the operation was cancelled.

276

<tbody>

277

<tr>

278

<td class="parameter_name">cancellable</td>

279

280

<td class="parameter_annotations">[<acronym title="NULL is OK, both for passing and for returning.">allow-none</acronym>]</td>

281

</tr>

282

<tr>

283

<td class="parameter_name">error</td>

284

<td class="parameter_description"><a href="http://library.gnome.org/devel/glib/unstable/glib-Error-Reporting.html#GError">GError</a> to append error state to</td>

284

<td class="parameter_description"><a href="../glib/glib-Error-Reporting.html#GError">GError</a> to append error state to</td>

285

286

</tr>

287

</tbody>

289

</div>

290

291

<a name="id-1.4.5.2.9.4.6"></a><h4>Returns</h4>

292

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

293

was cancelled, <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> if it was not

292

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

293

was cancelled, <a href="../glib/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> if it was not

294

295

</div>

296

</div>

335

<hr>

336

337

<a name="g-cancellable-make-pollfd"></a><h3>g_cancellable_make_pollfd ()</h3>

338

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

338

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

339

g_cancellable_make_pollfd (<code><a class="link" href="GCancellable.html" title="GCancellable">GCancellable</a> *cancellable</code>,

340

<code><a href="http://library.gnome.org/devel/glib/unstable/glib-The-Main-Event-Loop.html#GPollFD">GPollFD</a> *pollfd</code>);</pre>

341

Creates a <a href="http://library.gnome.org/devel/glib/unstable/glib-The-Main-Event-Loop.html#GPollFD">GPollFD</a> corresponding to <code>cancellable</code>

340

<code><a href="../glib/glib-The-Main-Event-Loop.html#GPollFD">GPollFD</a> *pollfd</code>);</pre>

341

Creates a <a href="../glib/glib-The-Main-Event-Loop.html#GPollFD">GPollFD</a> corresponding to <code>cancellable</code>

342

; this can be passed

343

to <a href="http://library.gnome.org/devel/glib/unstable/glib-The-Main-Event-Loop.html#g-poll"><code class="function">g_poll()</code></a> and used to poll for cancellation. This is useful both

343

to <a href="../glib/glib-The-Main-Event-Loop.html#g-poll"><code class="function">g_poll()</code></a> and used to poll for cancellation. This is useful both

344

for unix systems without a native poll and for portability to

345

windows.

346

When this function returns <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a>, you should use

346

When this function returns <a href="../glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a>, you should use

347

<a class="link" href="GCancellable.html#g-cancellable-release-fd" title="g_cancellable_release_fd ()"><code class="function">g_cancellable_release_fd()</code></a> to free up resources allocated for the

348

<code>pollfd</code>

349

. After a <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> return, do not call <a class="link" href="GCancellable.html#g-cancellable-release-fd" title="g_cancellable_release_fd ()"><code class="function">g_cancellable_release_fd()</code></a>.

350

If this function returns <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a>, either no <code>cancellable</code>

349

. After a <a href="../glib/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> return, do not call <a class="link" href="GCancellable.html#g-cancellable-release-fd" title="g_cancellable_release_fd ()"><code class="function">g_cancellable_release_fd()</code></a>.

350

If this function returns <a href="../glib/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a>, either no <code>cancellable</code>

351

was given or

352

resource limits prevent this function from allocating the necessary

353

structures for polling. (On Linux, you will likely have reached

368

<tbody>

369

<tr>

370

<td class="parameter_name">cancellable</td>

371

372

<td class="parameter_annotations">[<acronym title="NULL is OK, both for passing and for returning.">allow-none</acronym>]</td>

373

</tr>

374

<tr>

375

<td class="parameter_name">pollfd</td>

376

<td class="parameter_description">a pointer to a <a href="http://library.gnome.org/devel/glib/unstable/glib-The-Main-Event-Loop.html#GPollFD">GPollFD</a></td>

376

<td class="parameter_description">a pointer to a <a href="../glib/glib-The-Main-Event-Loop.html#GPollFD">GPollFD</a></td>

377

378

</tr>

379

</tbody>

381

</div>

382

383

<a name="id-1.4.5.2.9.6.9"></a><h4>Returns</h4>

384

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

385

was successfully initialized, <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> on

384

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

385

was successfully initialized, <a href="../glib/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> on

386

failure to prepare the cancellable.

387

388

</div>

423

<hr>

424

425

<a name="g-cancellable-source-new"></a><h3>g_cancellable_source_new ()</h3>

426

<pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-The-Main-Event-Loop.html#GSource">GSource</a> *

426

<pre class="programlisting"><a href="../glib/glib-The-Main-Event-Loop.html#GSource">GSource</a> *

427

g_cancellable_source_new (<code><a class="link" href="GCancellable.html" title="GCancellable">GCancellable</a> *cancellable</code>);</pre>

428

Creates a source that triggers if <code>cancellable</code>

429

is cancelled and

430

calls its callback of type <a class="link" href="GCancellable.html#GCancellableSourceFunc" title="GCancellableSourceFunc ()">GCancellableSourceFunc</a>. This is

431

primarily useful for attaching to another (non-cancellable) source

432

with <a href="http://library.gnome.org/devel/glib/unstable/glib-The-Main-Event-Loop.html#g-source-add-child-source"><code class="function">g_source_add_child_source()</code></a> to add cancellability to it.

433

For convenience, you can call this with a <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> <a class="link" href="GCancellable.html" title="GCancellable">GCancellable</a>,

432

with <a href="../glib/glib-The-Main-Event-Loop.html#g-source-add-child-source"><code class="function">g_source_add_child_source()</code></a> to add cancellability to it.

433

For convenience, you can call this with a <a href="../glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> <a class="link" href="GCancellable.html" title="GCancellable">GCancellable</a>,

434

in which case the source will never trigger.

435

436

<a name="id-1.4.5.2.9.8.6"></a><h4>Parameters</h4>

442

</colgroup>

443

444

<td class="parameter_name">cancellable</td>

445

<td class="parameter_description"> a <a class="link" href="GCancellable.html" title="GCancellable">GCancellable</a>, or <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>. </td>

445

<td class="parameter_description"> a <a class="link" href="GCancellable.html" title="GCancellable">GCancellable</a>, or <a href="../glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>. </td>

446

<td class="parameter_annotations">[<acronym title="NULL is OK, both for passing and for returning.">allow-none</acronym>]</td>

447

</tr></tbody>

448

</table></div>

449

</div>

450

451

<a name="id-1.4.5.2.9.8.7"></a><h4>Returns</h4>

452

the new <a href="http://library.gnome.org/devel/glib/unstable/glib-The-Main-Event-Loop.html#GSource">GSource</a>.

452

the new <a href="../glib/glib-The-Main-Event-Loop.html#GSource">GSource</a>.

453

[<acronym title="Free data after the code is done.">transfer full</acronym>]

454

</div>

455

Since 2.28

457

<hr>

458

459

<a name="GCancellableSourceFunc"></a><h3>GCancellableSourceFunc ()</h3>

460

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

460

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

461

(*GCancellableSourceFunc) (<code><a class="link" href="GCancellable.html" title="GCancellable">GCancellable</a> *cancellable</code>,

462

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

463

This is the function type of the callback used for the <a href="http://library.gnome.org/devel/glib/unstable/glib-The-Main-Event-Loop.html#GSource">GSource</a>

462

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

463

This is the function type of the callback used for the <a href="../glib/glib-The-Main-Event-Loop.html#GSource">GSource</a>

464

returned by <a class="link" href="GCancellable.html#g-cancellable-source-new" title="g_cancellable_source_new ()"><code class="function">g_cancellable_source_new()</code></a>.

465

466

<a name="id-1.4.5.2.9.9.5"></a><h4>Parameters</h4>

486

</div>

487

488

<a name="id-1.4.5.2.9.9.6"></a><h4>Returns</h4>

489

it should return <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> if the source should be removed.

489

it should return <a href="../glib/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> if the source should be removed.

490

491

</div>

492

Since 2.28

500

501

<a name="id-1.4.5.2.9.10.5"></a><h4>Returns</h4>

502

a <a class="link" href="GCancellable.html" title="GCancellable">GCancellable</a> from the top

503

of the stack, or <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if the stack is empty.

503

of the stack, or <a href="../glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if the stack is empty.

504

[<acronym title="NULL may be passed as the value in, out, in-out; or as a return value.">nullable</acronym>][<acronym title="Don't free data after the code is done.">transfer none</acronym>]

505

</div>

506

</div>

585

<hr>

586

587

<a name="g-cancellable-connect"></a><h3>g_cancellable_connect ()</h3>

588

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

588

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

589

g_cancellable_connect (<code><a class="link" href="GCancellable.html" title="GCancellable">GCancellable</a> *cancellable</code>,

590

<code><a href="http://library.gnome.org/devel/gobject/unstable/gobject-Closures.html#GCallback">GCallback</a> callback</code>,

591

<code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer">gpointer</a> data</code>,

592

<code><a href="http://library.gnome.org/devel/glib/unstable/glib-Datasets.html#GDestroyNotify">GDestroyNotify</a> data_destroy_func</code>);</pre>

590

<code><a href="../gobject/gobject-Closures.html#GCallback">GCallback</a> callback</code>,

591

<code><a href="../glib/glib-Basic-Types.html#gpointer">gpointer</a> data</code>,

592

<code><a href="../glib/glib-Datasets.html#GDestroyNotify">GDestroyNotify</a> data_destroy_func</code>);</pre>

593

Convenience function to connect to the <a class="link" href="GCancellable.html#GCancellable-cancelled" title="The “cancelled” signal">“cancelled”</a>

594

signal. Also handles the race condition that may happen

595

if the cancellable is cancelled right before connecting.

626

</tr>

627

<tr>

628

<td class="parameter_name">callback</td>

629

<td class="parameter_description">The <a href="http://library.gnome.org/devel/gobject/unstable/gobject-Closures.html#GCallback">GCallback</a> to connect.</td>

629

<td class="parameter_description">The <a href="../gobject/gobject-Closures.html#GCallback">GCallback</a> to connect.</td>

630

631

</tr>

632

<tr>

638

<tr>

639

<td class="parameter_name">data_destroy_func</td>

640

<td class="parameter_description"> Free function for <code>data</code>

641

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

641

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

642

<td class="parameter_annotations">[<acronym title="NULL is OK, both for passing and for returning.">allow-none</acronym>]</td>

643

</tr>

644

</tbody>

658

<a name="g-cancellable-disconnect"></a><h3>g_cancellable_disconnect ()</h3>

659

<pre class="programlisting">void

660

g_cancellable_disconnect (<code><a class="link" href="GCancellable.html" title="GCancellable">GCancellable</a> *cancellable</code>,

661

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

661

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

662

Disconnects a handler from a cancellable instance similar to

663

<a href="http://library.gnome.org/devel/gobject/unstable/gobject-Signals.html#g-signal-handler-disconnect"><code class="function">g_signal_handler_disconnect()</code></a>. Additionally, in the event that a

663

<a href="../gobject/gobject-Signals.html#g-signal-handler-disconnect"><code class="function">g_signal_handler_disconnect()</code></a>. Additionally, in the event that a

664

signal handler is currently running, this call will block until the

665

handler has finished. Calling this function from a

666

<a class="link" href="GCancellable.html#GCancellable-cancelled" title="The “cancelled” signal">“cancelled”</a> signal handler will therefore result in a

670

signal handler is removed. See <a class="link" href="GCancellable.html#GCancellable-cancelled" title="The “cancelled” signal">“cancelled”</a> for

671

details on how to use this.

672

If <code>cancellable</code>

673

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

673

is <a href="../glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> or <code>handler_id</code>

674

is <code class="literal">0</code> this function does

675

nothing.

676

684

<tbody>

685

<tr>

686

<td class="parameter_name">cancellable</td>

687

<td class="parameter_description"> A <a class="link" href="GCancellable.html" title="GCancellable">GCancellable</a> or <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>. </td>

687

<td class="parameter_description"> A <a class="link" href="GCancellable.html" title="GCancellable">GCancellable</a> or <a href="../glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>. </td>

688

<td class="parameter_annotations">[<acronym title="NULL is OK, both for passing and for returning.">allow-none</acronym>]</td>

689

</tr>

690

<tr>

747

<a name="GCancellable-cancelled"></a><h3>The <code class="literal">“cancelled”</code> signal</h3>

748

<pre class="programlisting">void

749

user_function (<a class="link" href="GCancellable.html" title="GCancellable">GCancellable</a> *cancellable,

750

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

750

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

751

Emitted when the operation has been cancelled.

752

Can be used by implementations of cancellable operations. If the

753

operation is cancelled from another thread, the signal will be

756

Note that disconnecting from this signal (or any signal) in a

757

multi-threaded program is prone to race conditions. For instance

758

it is possible that a signal handler may be invoked even after

759

a call to <a href="http://library.gnome.org/devel/gobject/unstable/gobject-Signals.html#g-signal-handler-disconnect"><code class="function">g_signal_handler_disconnect()</code></a> for that handler has

759

a call to <a href="../gobject/gobject-Signals.html#g-signal-handler-disconnect"><code class="function">g_signal_handler_disconnect()</code></a> for that handler has

760

already returned.

761

There is also a problem when cancellation happens right before

762

connecting to the signal. If this happens the signal will

792

793

794

21</pre></td>

795

<td class="listing_code"><pre class="programlisting">// Make sure we don't do unnecessary work if already cancelled

796

if (<a href="GCancellable.html#g-cancellable-set-error-if-cancelled">g_cancellable_set_error_if_cancelled</a> (cancellable, error))

797

return;

798

799

// Set up all the data needed to be able to handle cancellation

800

// of the operation

801

my_data = my_data_new (...);

802

803

id = 0;

804

if (cancellable)

805

id = <a href="GCancellable.html#g-cancellable-connect">g_cancellable_connect</a> (cancellable,

806

<a href="http://library.gnome.org/devel/gobject/unstable/gobject-Closures.html#G-CALLBACK:CAPS">G_CALLBACK</a> (cancelled_handler)

807

data, <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#NULL:CAPS">NULL</a>);

808

809

// cancellable operation here...

810

811

<a href="GCancellable.html#g-cancellable-disconnect">g_cancellable_disconnect</a> (cancellable, id);

812

813

// cancelled_handler is never called after this, it is now safe

814

// to free the data

815

my_data_free (my_data);</pre></td>

795

<td class="listing_code"><pre class="programlisting">// Make sure we don't do unnecessary work if already cancelled

796

if (<a href="GCancellable.html#g-cancellable-set-error-if-cancelled">g_cancellable_set_error_if_cancelled</a> (cancellable, error))

797

return;

798

799

// Set up all the data needed to be able to handle cancellation

800

// of the operation

801

my_data = my_data_new (...);

802

803

id = 0;

804

if (cancellable)

805

id = <a href="GCancellable.html#g-cancellable-connect">g_cancellable_connect</a> (cancellable,

806

<a href="../gobject/gobject-Closures.html#G-CALLBACK:CAPS">G_CALLBACK</a> (cancelled_handler)

807

data, NULL);

808

809

// cancellable operation here...

810

811

<a href="GCancellable.html#g-cancellable-disconnect">g_cancellable_disconnect</a> (cancellable, id);

812

813

// cancelled_handler is never called after this, it is now safe

814

// to free the data

815

my_data_free (my_data);</pre></td>

816

</tr>

817

</tbody>

818

</table>

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