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

<a class="link" href="glib-The-Main-Event-Loop.html#GMainContext" title="GMainContext">GMainContext</a>, and will be checked and dispatched for all main

897

loops associated with that GMainContext.

898

GTK+ contains wrappers of some of these functions, e.g. <a href="http://developer.gnome.org/gtk2/gtk3-General.html#gtk-main"><code class="function">gtk_main()</code></a>,

899

<a href="http://developer.gnome.org/gtk2/gtk3-General.html#gtk-main-quit"><code class="function">gtk_main_quit()</code></a> and <a href="http://developer.gnome.org/gtk2/gtk3-General.html#gtk-events-pending"><code class="function">gtk_events_pending()</code></a>.

898

GTK+ contains wrappers of some of these functions, e.g. <code class="function">gtk_main()</code>,

899

<code class="function">gtk_main_quit()</code> and <code class="function">gtk_events_pending()</code>.

900

901

<a name="id-1.4.2.6.9"></a><h4>Creating new source types</h4>

902

One of the unusual features of the <a class="link" href="glib-The-Main-Event-Loop.html#GMainLoop" title="GMainLoop">GMainLoop</a> functionality

1478

g_main_context_find_source_by_id (<code><a class="link" href="glib-The-Main-Event-Loop.html#GMainContext" title="GMainContext">GMainContext</a> *context</code>,

1479

<code><a class="link" href="glib-Basic-Types.html#guint" title="guint">guint</a> source_id</code>);</pre>

1480

Finds a <a class="link" href="glib-The-Main-Event-Loop.html#GSource" title="struct GSource">GSource</a> given a pair of context and ID.

1481

It is a programmer error to attempt to lookup a non-existent source.

1482

More specifically: source IDs can be reissued after a source has been

1483

destroyed and therefore it is never valid to use this function with a

1484

source ID which may have already been removed. An example is when

1485

scheduling an idle to run in another thread with <a class="link" href="glib-The-Main-Event-Loop.html#g-idle-add" title="g_idle_add ()"><code class="function">g_idle_add()</code></a>: the

1486

idle may already have run and been removed by the time this function

1487

is called on its (now invalid) source ID. This source ID may have

1488

been reissued, leading to the operation being performed against the

1489

wrong source.

1481

1490

1482

<a name="id-1.4.2.7.22.5"></a><h4>Parameters</h4>

1491

<a name="id-1.4.2.7.22.7"></a><h4>Parameters</h4>

1483

1492

1484

1493

1485

1494

1501

1510

</table></div>

1502

1511

</div>

1503

1512

1504

<a name="id-1.4.2.7.22.6"></a><h4>Returns</h4>

1505

the <a class="link" href="glib-The-Main-Event-Loop.html#GSource" title="struct GSource">GSource</a> if found, otherwise, <a class="link" href="glib-Standard-Macros.html#NULL:CAPS" title="NULL"><code class="literal">NULL</code></a>.

1513

<a name="id-1.4.2.7.22.8"></a><h4>Returns</h4>

1514

the <a class="link" href="glib-The-Main-Event-Loop.html#GSource" title="struct GSource">GSource</a>.

1506

1515

[<acronym title="Don't free data after the code is done.">transfer none</acronym>]

1507

1516

</div>

1508

1517

</div>

1614

1623

1615

1624

1616

1625

6</pre></td>

1617

<td class="listing_code"><pre class="programlisting">#define NUM_TASKS 10

1618

static volatile gint tasks_remaining = NUM_TASKS;

1619

...

1620

1621

while (<a href="glib-Atomic-Operations.html#g-atomic-int-get">g_atomic_int_get</a> (&tasks_remaining) != 0)

1622

<a href="glib-The-Main-Event-Loop.html#g-main-context-iteration">g_main_context_iteration</a> (<a href="glib-Standard-Macros.html#NULL:CAPS">NULL</a>, <a href="glib-Standard-Macros.html#TRUE:CAPS">TRUE</a>);</pre></td>

1626

<td class="listing_code"><pre class="programlisting">#define NUM_TASKS 10

1627

static volatile gint tasks_remaining = NUM_TASKS;

1628

...

1629

1630

while (<a href="glib-Atomic-Operations.html#g-atomic-int-get">g_atomic_int_get</a> (&tasks_remaining) != 0)

1631

<a href="glib-The-Main-Event-Loop.html#g-main-context-iteration">g_main_context_iteration</a> (NULL, TRUE);</pre></td>

1623

1632

</tr>

1624

1633

</tbody>

1625

1634

</table>

1635

1644

1636

1645

1637

1646

4</pre></td>

1638

<td class="listing_code"><pre class="programlisting">perform_work();

1647

<td class="listing_code"><pre class="programlisting">perform_work();

1639

1648

1640

if (<a href="glib-Atomic-Operations.html#g-atomic-int-dec-and-test">g_atomic_int_dec_and_test</a> (&tasks_remaining))

1641

<a href="glib-The-Main-Event-Loop.html#g-main-context-wakeup">g_main_context_wakeup</a> (<a href="glib-Standard-Macros.html#NULL:CAPS">NULL</a>);</pre></td>

1649

if (<a href="glib-Atomic-Operations.html#g-atomic-int-dec-and-test">g_atomic_int_dec_and_test</a> (&tasks_remaining))

1650

<a href="glib-The-Main-Event-Loop.html#g-main-context-wakeup">g_main_context_wakeup</a> (NULL);</pre></td>

1642

1651

</tr>

1643

1652

</tbody>

1644

1653

</table>

2205

2214

2206

2215

2207

2216

27</pre></td>

2208

<td class="listing_code"><pre class="programlisting">static GList *free_list;

2209

2210

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

2211

allocate_memory (gsize size)

2212

{

2213

gpointer result = <a href="glib-Memory-Allocation.html#g-malloc">g_malloc</a> (size);

2214

free_list = <a href="glib-Doubly-Linked-Lists.html#g-list-prepend">g_list_prepend</a> (free_list, result);

2215

return result;

2216

}

2217

2218

void

2219

free_allocated_memory (void)

2220

{

2221

GList *l;

2222

for (l = free_list; l; l = l->next);

2223

<a href="glib-Memory-Allocation.html#g-free">g_free</a> (l->data);

2224

<a href="glib-Doubly-Linked-Lists.html#g-list-free">g_list_free</a> (free_list);

2225

free_list = <a href="glib-Standard-Macros.html#NULL:CAPS">NULL</a>;

2226

}

2227

2228

[...]

2229

2230

while (<a href="glib-Standard-Macros.html#TRUE:CAPS">TRUE</a>);

2231

{

2232

2233

free_allocated_memory();

2234

}</pre></td>

2217

<td class="listing_code"><pre class="programlisting">static GList *free_list;

2218

2219

gpointer

2220

allocate_memory (gsize size)

2221

{

2222

gpointer result = <a href="glib-Memory-Allocation.html#g-malloc">g_malloc</a> (size);

2223

free_list = <a href="glib-Doubly-Linked-Lists.html#g-list-prepend">g_list_prepend</a> (free_list, result);

2224

return result;

2225

}

2226

2227

void

2228

free_allocated_memory (void)

2229

{

2230

GList *l;

2231

for (l = free_list; l; l = l->next);

2232

<a href="glib-Memory-Allocation.html#g-free">g_free</a> (l->data);

2233

<a href="glib-Doubly-Linked-Lists.html#g-list-free">g_list_free</a> (free_list);

2234

free_list = NULL;

2235

}

2236

2237

[...]

2238

2239

while (TRUE);

2240

{

2241

2242

free_allocated_memory();

2243

}</pre></td>

2235

2244

</tr>

2236

2245

</tbody>

2237

2246

</table>

2278

2287

2279

2288

2280

2289

30</pre></td>

2281

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

2282

2283

{

2284

FreeListBlock *block = <a href="glib-Memory-Allocation.html#g-new">g_new</a> (FreeListBlock, 1);

2285

block->mem = <a href="glib-Memory-Allocation.html#g-malloc">g_malloc</a> (size);

2286

block->depth = <a href="glib-The-Main-Event-Loop.html#g-main-depth">g_main_depth</a> ();

2287

2288

return block->mem;

2289

}

2290

<td class="listing_code"><pre class="programlisting">gpointer

2291

allocate_memory (gsize size)

2292

{

2293

FreeListBlock *block = <a href="glib-Memory-Allocation.html#g-new">g_new</a> (FreeListBlock, 1);

2294

block->mem = <a href="glib-Memory-Allocation.html#g-malloc">g_malloc</a> (size);

2295

block->depth = <a href="glib-The-Main-Event-Loop.html#g-main-depth">g_main_depth</a> ();

2296

2297

return block->mem;

2298

}

2290

2299

2291

void

2292

free_allocated_memory (void)

2293

{

2294

GList *l;

2295

2296

int depth = <a href="glib-The-Main-Event-Loop.html#g-main-depth">g_main_depth</a> ();

2297

2298

{

2299

GList *next = l->next;

2300

2301

if (block->depth > depth)

2302

{

2303

<a href="glib-Memory-Allocation.html#g-free">g_free</a> (block->mem);

2304

2305

free_list = <a href="glib-Doubly-Linked-Lists.html#g-list-delete-link">g_list_delete_link</a> (free_list, l);

2306

}

2307

2308

l = next;

2309

}

2310

}</pre></td>

2300

void

2301

free_allocated_memory (void)

2302

{

2303

GList *l;

2304

2305

int depth = <a href="glib-The-Main-Event-Loop.html#g-main-depth">g_main_depth</a> ();

2306

for (l = free_list; l; );

2307

{

2308

GList *next = l->next;

2309

FreeListBlock *block = l->data;

2310

if (block->depth > depth)

2311

{

2312

<a href="glib-Memory-Allocation.html#g-free">g_free</a> (block->mem);

2313

<a href="glib-Memory-Allocation.html#g-free">g_free</a> (block);

2314

free_list = <a href="glib-Doubly-Linked-Lists.html#g-list-delete-link">g_list_delete_link</a> (free_list, l);

2315

}

2316

2317

l = next;

2318

}

2319

}</pre></td>

2311

2320

</tr>

2312

2321

</tbody>

2313

2322

</table>

2326

2335

many things that the user could do. Instead, you can use the

2327

2336

following techniques:

2328

2337

2329

<li class="listitem">Use <a href="http://developer.gnome.org/gtk2/GtkWidget.html#gtk-widget-set-sensitive"><code class="function">gtk_widget_set_sensitive()</code></a> or modal dialogs to prevent

2338

<li class="listitem">Use <code class="function">gtk_widget_set_sensitive()</code> or modal dialogs to prevent

2330

2339

the user from interacting with elements while the main

2331

2340

loop is recursing.</li>

2332

2341

<li class="listitem">Avoid main loop recursion in situations where you can't handle

2579

2588

started while the non-default context is active.

2580

2589

Beware that libraries that predate this function may not correctly

2581

2590

handle being used from a thread with a thread-default context. Eg,

2582

see <a href="http://library.gnome.org/devel/gio/unstable/GFile.html#g-file-supports-thread-contexts"><code class="function">g_file_supports_thread_contexts()</code></a>.

2591

see <a href="../gio/GFile.html#g-file-supports-thread-contexts"><code class="function">g_file_supports_thread_contexts()</code></a>.

2583

2592

2584

2593

<a name="id-1.4.2.7.46.7"></a><h4>Parameters</h4>

2585

2594

3402

3411

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

3403

3412

<pre class="programlisting">void

3404

3413

(*GSourceDummyMarshal) (<code>void</code>);</pre>

3405

This is just a placeholder for <a href="http://library.gnome.org/devel/gobject/unstable/gobject-Closures.html#GClosureMarshal">GClosureMarshal</a>,

3414

This is just a placeholder for <a href="../gobject/gobject-Closures.html#GClosureMarshal">GClosureMarshal</a>,

3406

3415

which cannot be used here for dependency reasons.

3407

3416

</div>

3408

3417

<hr>

3637

3646

3638

3647

3639

3648

29</pre></td>

3640

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

3641

idle_callback (gpointer data)

3642

{

3643

3644

3645

<a href="http://developer.gnome.org/gdk2/gdk3-Threads.html#GDK-THREADS-ENTER:CAPS">GDK_THREADS_ENTER</a> ();

3646

// do stuff with self

3647

3648

<a href="http://developer.gnome.org/gdk2/gdk3-Threads.html#GDK-THREADS-LEAVE:CAPS">GDK_THREADS_LEAVE</a> ();

3649

3650

return <a href="glib-The-Main-Event-Loop.html#G-SOURCE-REMOVE:CAPS">G_SOURCE_REMOVE</a>;

3651

}

3652

3653

static void

3654

some_widget_do_stuff_later (SomeWidget *self)

3655

{

3656

self->idle_id = <a href="glib-The-Main-Event-Loop.html#g-idle-add">g_idle_add</a> (idle_callback, self);

3657

}

3658

3659

static void

3660

some_widget_finalize (GObject *object)

3661

{

3662

SomeWidget *self = SOME_WIDGET (object);

3663

3664

if (self->idle_id)

3665

<a href="glib-The-Main-Event-Loop.html#g-source-remove">g_source_remove</a> (self->idle_id);

3666

3667

<a href="http://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#G-OBJECT-CLASS:CAPS">G_OBJECT_CLASS</a> (parent_class)->finalize (object);

3668

}</pre></td>

3649

<td class="listing_code"><pre class="programlisting">static gboolean

3650

idle_callback (gpointer data)

3651

{

3652

SomeWidget *self = data;

3653

3654

GDK_THREADS_ENTER ();

3655

// do stuff with self

3656

self->idle_id = 0;

3657

GDK_THREADS_LEAVE ();

3658

3659

return G_SOURCE_REMOVE;

3660

}

3661

3662

static void

3663

some_widget_do_stuff_later (SomeWidget *self)

3664

{

3665

self->idle_id = <a href="glib-The-Main-Event-Loop.html#g-idle-add">g_idle_add</a> (idle_callback, self);

3666

}

3667

3668

static void

3669

some_widget_finalize (GObject *object)

3670

{

3671

SomeWidget *self = SOME_WIDGET (object);

3672

3673

if (self->idle_id)

3674

<a href="glib-The-Main-Event-Loop.html#g-source-remove">g_source_remove</a> (self->idle_id);

3675

3676

<a href="../gobject/gobject-The-Base-Object-Type.html#G-OBJECT-CLASS:CAPS">G_OBJECT_CLASS</a> (parent_class)->finalize (object);

3677

}</pre></td>

3669

3678

</tr>

3670

3679

</tbody>

3671

3680

</table>

3695

3704

3696

3705

3697

3706

14</pre></td>

3698

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

3699

3700

{

3701

3702

3703

3704

if (!<a href="glib-The-Main-Event-Loop.html#g-source-is-destroyed">g_source_is_destroyed</a> (<a href="glib-The-Main-Event-Loop.html#g-main-current-source">g_main_current_source</a> ()))

3705

{

3706

// do stuff with self

3707

}

3708

3709

3710

return <a href="glib-Standard-Macros.html#FALSE:CAPS">FALSE</a>;

3711

}</pre></td>

3707

<td class="listing_code"><pre class="programlisting">static gboolean

3708

idle_callback (gpointer data)

3709

{

3710

SomeWidget *self = data;

3711

3712

GDK_THREADS_ENTER ();

3713

if (!<a href="glib-The-Main-Event-Loop.html#g-source-is-destroyed">g_source_is_destroyed</a> (<a href="glib-The-Main-Event-Loop.html#g-main-current-source">g_main_current_source</a> ()))

3714

{

3715

// do stuff with self

3716

}

3717

GDK_THREADS_LEAVE ();

3718

3719

return FALSE;

3720

}</pre></td>

3712

3721

</tr>

3713

3722

</tbody>

3714

3723

</table>

3897

3906

<a name="g-source-get-name"></a><h3>g_source_get_name ()</h3>

3898

3907

<pre class="programlisting">const char *

3899

3908

g_source_get_name (<code><a class="link" href="glib-The-Main-Event-Loop.html#GSource" title="struct GSource">GSource</a> *source</code>);</pre>

3900

Gets a name for the source, used in debugging and profiling.

3901

The name may be <a class="link" href="glib-Standard-Macros.html#NULL:CAPS" title="NULL">NULL</a> if it has never been set with

3902

<a class="link" href="glib-The-Main-Event-Loop.html#g-source-set-name" title="g_source_set_name ()"><code class="function">g_source_set_name()</code></a>.

3909

Gets a name for the source, used in debugging and profiling. The

3910

name may be <a class="link" href="glib-Standard-Macros.html#NULL:CAPS" title="NULL">NULL</a> if it has never been set with <a class="link" href="glib-The-Main-Event-Loop.html#g-source-set-name" title="g_source_set_name ()"><code class="function">g_source_set_name()</code></a>.

3903

3911

3904

3912

<a name="id-1.4.2.7.76.5"></a><h4>Parameters</h4>

3905

3913

3935

3943

or "GTK+ repaint idle handler" or whatever it is.

3936

3944

It is permitted to call this function multiple times, but is not

3937

3945

recommended due to the potential performance impact. For example,

3938

one could change the name in the "check" function of a <a class="link" href="glib-The-Main-Event-Loop.html#GSourceFuncs" title="struct GSourceFuncs">GSourceFuncs</a>

3946

one could change the name in the "check" function of a <a class="link" href="glib-The-Main-Event-Loop.html#GSourceFuncs" title="struct GSourceFuncs">GSourceFuncs</a>

3939

3947

to include details like the event type in the source name.

3948

Use caution if changing the name while another thread may be

3949

accessing it with <a class="link" href="glib-The-Main-Event-Loop.html#g-source-get-name" title="g_source_get_name ()"><code class="function">g_source_get_name()</code></a>; that function does not copy

3950

the value, and changing the value will free it while the other thread

3951

may be attempting to use it.

3940

3952

3941

<a name="id-1.4.2.7.77.7"></a><h4>Parameters</h4>

3953

<a name="id-1.4.2.7.77.8"></a><h4>Parameters</h4>

3942

3954

3943

3955

3944

3956

3970

3982

Sets the name of a source using its ID.

3971

3983

This is a convenience utility to set source names from the return

3972

3984

value of <a class="link" href="glib-The-Main-Event-Loop.html#g-idle-add" title="g_idle_add ()"><code class="function">g_idle_add()</code></a>, <a class="link" href="glib-The-Main-Event-Loop.html#g-timeout-add" title="g_timeout_add ()"><code class="function">g_timeout_add()</code></a>, etc.

3985

It is a programmer error to attempt to set the name of a non-existent

3986

source.

3987

More specifically: source IDs can be reissued after a source has been

3988

destroyed and therefore it is never valid to use this function with a

3989

source ID which may have already been removed. An example is when

3990

scheduling an idle to run in another thread with <a class="link" href="glib-The-Main-Event-Loop.html#g-idle-add" title="g_idle_add ()"><code class="function">g_idle_add()</code></a>: the

3991

idle may already have run and been removed by the time this function

3992

is called on its (now invalid) source ID. This source ID may have

3993

been reissued, leading to the operation being performed against the

3994

wrong source.

3973

3995

3974

<a name="id-1.4.2.7.78.6"></a><h4>Parameters</h4>

3996

<a name="id-1.4.2.7.78.8"></a><h4>Parameters</h4>

3975

3997

3976

3998

3977

3999

4512

4534

its own prepare/check functions indicate that it is ready.)

4513

4535

If you don't need <code>child_source</code>

4514

4536

to do anything on its own when it

4515

triggers, you can call <a href="http://library.gnome.org/devel/gobject/unstable/gobject-Closures.html#g-source-set-dummy-callback"><code class="function">g_source_set_dummy_callback()</code></a> on it to set a

4537

triggers, you can call <a href="../gobject/gobject-Closures.html#g-source-set-dummy-callback"><code class="function">g_source_set_dummy_callback()</code></a> on it to set a

4516

4538

callback that does nothing (except return <a class="link" href="glib-Standard-Macros.html#TRUE:CAPS" title="TRUE"><code class="literal">TRUE</code></a> if appropriate).

4517

4539

<code>source</code>

4518

4540

will hold a reference on <code>child_source</code>

4665

4687

See also <a class="link" href="glib-The-Main-Event-Loop.html#g-source-destroy" title="g_source_destroy ()"><code class="function">g_source_destroy()</code></a>. You must use <a class="link" href="glib-The-Main-Event-Loop.html#g-source-destroy" title="g_source_destroy ()"><code class="function">g_source_destroy()</code></a> for sources

4666

4688

added to a non-default main context.

4667

4689

It is a programmer error to attempt to remove a non-existent source.

4690

More specifically: source IDs can be reissued after a source has been

4691

destroyed and therefore it is never valid to use this function with a

4692

source ID which may have already been removed. An example is when

4693

scheduling an idle to run in another thread with <a class="link" href="glib-The-Main-Event-Loop.html#g-idle-add" title="g_idle_add ()"><code class="function">g_idle_add()</code></a>: the

4694

idle may already have run and been removed by the time this function

4695

is called on its (now invalid) source ID. This source ID may have

4696

been reissued, leading to the operation being performed against the

4697

wrong source.

4668

4698

4669

<a name="id-1.4.2.7.95.8"></a><h4>Parameters</h4>

4699

<a name="id-1.4.2.7.95.9"></a><h4>Parameters</h4>

4670

4700

4671

4701

4672

4702

4681

4711

</table></div>

4682

4712

</div>

4683

4713

4684

<a name="id-1.4.2.7.95.9"></a><h4>Returns</h4>

4714

<a name="id-1.4.2.7.95.10"></a><h4>Returns</h4>

4685

4715

For historical reasons, this function always returns <a class="link" href="glib-Standard-Macros.html#TRUE:CAPS" title="TRUE"><code class="literal">TRUE</code></a>

4686

4716

4687

4717

</div>

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