Creates a new #GSource structure. The size is specified to
allow creating structures derived from #GSource that contain
additional data. The size passed in must be at least
sizeof (GSource).
The source will not initially be associated with any #GMainContext and must be added to one with g_source_attach() before it will be executed.
structure containing functions that implement the sources behavior.
size of the #GSource structure to create.
Adds child_source to source as a "polled" source; when source is
added to a #GMainContext, child_source will be automatically added
with the same priority, when child_source is triggered, it will
cause source to dispatch (in addition to calling its own
callback), and when source is destroyed, it will destroy
child_source as well. (source will also still be dispatched if
its own prepare/check functions indicate that it is ready.)
If you don't need child_source to do anything on its own when it
triggers, you can call g_source_set_dummy_callback() on it to set a
callback that does nothing (except return %TRUE if appropriate).
source will hold a reference on child_source while child_source
is attached to it.
This API is only intended to be used by implementations of #GSource. Do not call this API on a #GSource that you did not create.
Adds a file descriptor to the set of file descriptors polled for
this source. This is usually combined with g_source_new() to add an
event source. The event source's check function will typically test
the revents field in the #GPollFD struct and return %TRUE if events need
to be processed.
This API is only intended to be used by implementations of #GSource. Do not call this API on a #GSource that you did not create.
Using this API forces the linear scanning of event sources on each main loop iteration. Newly-written event sources should try to use g_source_add_unix_fd() instead of this API.
Monitors fd for the IO events in events.
The tag returned by this function can be used to remove or modify the monitoring of the fd using g_source_remove_unix_fd() or g_source_modify_unix_fd().
It is not necessary to remove the fd before destroying the source; it will be cleaned up automatically.
This API is only intended to be used by implementations of #GSource. Do not call this API on a #GSource that you did not create.
As the name suggests, this function is not available on Windows.
the fd to monitor
an event mask
Adds a #GSource to a context so that it will be executed within
that context. Remove it by calling g_source_destroy().
This function is safe to call from any thread, regardless of which thread
the context is running in.
a #GMainContext (if %NULL, the default context will be used)
Removes a source from its #GMainContext, if any, and mark it as destroyed. The source cannot be subsequently added to another context. It is safe to call this on sources which have already been removed from their context.
This does not unref the #GSource: if you still hold a reference, use g_source_unref() to drop it.
This function is safe to call from any thread, regardless of which thread the #GMainContext is running in.
If the source is currently attached to a #GMainContext, destroying it will effectively unset the callback similar to calling g_source_set_callback(). This can mean, that the data's #GDestroyNotify gets called right away.
Checks whether a source is allowed to be called recursively. see g_source_set_can_recurse().
Gets the #GMainContext with which the source is associated.
You can call this on a source that has been destroyed, provided that the #GMainContext it was attached to still exists (in which case it will return that #GMainContext). In particular, you can always call this function on the source returned from g_main_current_source(). But calling this function on a source whose #GMainContext has been destroyed is an error.
This function ignores source and is otherwise the same as
g_get_current_time().
#GTimeVal structure in which to store current time.
Returns the numeric ID for a particular source. The ID of a source is a positive integer which is unique within a particular main loop context. The reverse mapping from ID to source is done by g_main_context_find_source_by_id().
You can only call this function while the source is associated to a #GMainContext instance; calling this function before g_source_attach() or after g_source_destroy() yields undefined behavior. The ID returned is unique within the #GMainContext instance passed to g_source_attach().
Gets a name for the source, used in debugging and profiling. The name may be #NULL if it has never been set with g_source_set_name().
Gets the priority of a source.
Gets the "ready time" of source, as set by
g_source_set_ready_time().
Any time before the current monotonic time (including 0) is an indication that the source will fire immediately.
Gets the time to be used when checking this source. The advantage of calling this function over calling g_get_monotonic_time() directly is that when checking multiple sources, GLib can cache a single value instead of having to repeatedly get the system monotonic time.
The time here is the system monotonic time, if available, or some other reasonable alternative otherwise. See g_get_monotonic_time().
Returns whether source has been destroyed.
This is important when you operate upon your objects from within idle handlers, but may have freed the object before the dispatch of your idle handler.
static gboolean
idle_callback (gpointer data)
{
SomeWidget *self = data;
g_mutex_lock (&self->idle_id_mutex);
// do stuff with self
self->idle_id = 0;
g_mutex_unlock (&self->idle_id_mutex);
return G_SOURCE_REMOVE;
}
static void
some_widget_do_stuff_later (SomeWidget *self)
{
g_mutex_lock (&self->idle_id_mutex);
self->idle_id = g_idle_add (idle_callback, self);
g_mutex_unlock (&self->idle_id_mutex);
}
static void
some_widget_init (SomeWidget *self)
{
g_mutex_init (&self->idle_id_mutex);
// ...
}
static void
some_widget_finalize (GObject *object)
{
SomeWidget *self = SOME_WIDGET (object);
if (self->idle_id)
g_source_remove (self->idle_id);
g_mutex_clear (&self->idle_id_mutex);
G_OBJECT_CLASS (parent_class)->finalize (object);
}
This will fail in a multi-threaded application if the widget is destroyed before the idle handler fires due to the use after free in the callback. A solution, to this particular problem, is to check to if the source has already been destroy within the callback.
static gboolean
idle_callback (gpointer data)
{
SomeWidget *self = data;
g_mutex_lock (&self->idle_id_mutex);
if (!g_source_is_destroyed (g_main_current_source ()))
{
// do stuff with self
}
g_mutex_unlock (&self->idle_id_mutex);
return FALSE;
}
Calls to this function from a thread other than the one acquired by the #GMainContext the #GSource is attached to are typically redundant, as the source could be destroyed immediately after this function returns. However, once a source is destroyed it cannot be un-destroyed, so this function can be used for opportunistic checks from any thread.
Updates the event mask to watch for the fd identified by tag.
tag is the tag returned from g_source_add_unix_fd().
If you want to remove a fd, don't set its event mask to zero. Instead, call g_source_remove_unix_fd().
This API is only intended to be used by implementations of #GSource. Do not call this API on a #GSource that you did not create.
As the name suggests, this function is not available on Windows.
the tag from g_source_add_unix_fd()
the new event mask to watch
Queries the events reported for the fd corresponding to tag on
source during the last poll.
The return value of this function is only defined when the function
is called from the check or dispatch functions for source.
This API is only intended to be used by implementations of #GSource. Do not call this API on a #GSource that you did not create.
As the name suggests, this function is not available on Windows.
the tag from g_source_add_unix_fd()
Removes a file descriptor from the set of file descriptors polled for this source.
This API is only intended to be used by implementations of #GSource. Do not call this API on a #GSource that you did not create.
Reverses the effect of a previous call to g_source_add_unix_fd().
You only need to call this if you want to remove an fd from being watched while keeping the same source around. In the normal case you will just want to destroy the source.
This API is only intended to be used by implementations of #GSource. Do not call this API on a #GSource that you did not create.
As the name suggests, this function is not available on Windows.
the tag from g_source_add_unix_fd()
Sets the callback function for a source. The callback for a source is called from the source's dispatch function.
The exact type of func depends on the type of source; ie. you
should not count on func being called with data as its first
parameter. Cast func with G_SOURCE_FUNC() to avoid warnings about
incompatible function types.
See [memory management of sources][mainloop-memory-management] for details
on how to handle memory management of data.
Typically, you won't use this function. Instead use functions specific to the type of source you are using, such as g_idle_add() or g_timeout_add().
It is safe to call this function multiple times on a source which has already been attached to a context. The changes will take effect for the next time the source is dispatched after this call returns.
Note that g_source_destroy() for a currently attached source has the effect of also unsetting the callback.
a callback function
Sets the callback function storing the data as a refcounted callback
"object". This is used internally. Note that calling
g_source_set_callback_indirect() assumes
an initial reference count on callback_data, and thus
callback_funcs->unref will eventually be called once more
than callback_funcs->ref.
It is safe to call this function multiple times on a source which has already been attached to a context. The changes will take effect for the next time the source is dispatched after this call returns.
pointer to callback data "object"
functions for reference counting callback_data and getting the callback and data
Sets whether a source can be called recursively. If can_recurse is
%TRUE, then while the source is being dispatched then this source
will be processed normally. Otherwise, all processing of this
source is blocked until the dispatch function returns.
whether recursion is allowed for this source
Sets the source functions (can be used to override default implementations) of an unattached source.
the new #GSourceFuncs
Sets a name for the source, used in debugging and profiling. The name defaults to #NULL.
The source name should describe in a human-readable way what the source does. For example, "X11 event queue" or "GTK+ repaint idle handler" or whatever it is.
It is permitted to call this function multiple times, but is not recommended due to the potential performance impact. For example, one could change the name in the "check" function of a #GSourceFuncs to include details like the event type in the source name.
Use caution if changing the name while another thread may be accessing it with g_source_get_name(); that function does not copy the value, and changing the value will free it while the other thread may be attempting to use it.
Also see g_source_set_static_name().
debug name for the source
Sets the priority of a source. While the main loop is being run, a source will be dispatched if it is ready to be dispatched and no sources at a higher (numerically smaller) priority are ready to be dispatched.
A child source always has the same priority as its parent. It is not permitted to change the priority of a source once it has been added as a child of another source.
the new priority.
Sets a #GSource to be dispatched when the given monotonic time is
reached (or passed). If the monotonic time is in the past (as it
always will be if ready_time is 0) then the source will be
dispatched immediately.
If ready_time is -1 then the source is never woken up on the basis
of the passage of time.
Dispatching the source does not reset the ready time. You should do so yourself, from the source dispatch function.
Note that if you have a pair of sources where the ready time of one suggests that it will be delivered first but the priority for the other suggests that it would be delivered first, and the ready time for both sources is reached during the same main context iteration, then the order of dispatch is undefined.
It is a no-op to call this function on a #GSource which has already been destroyed with g_source_destroy().
This API is only intended to be used by implementations of #GSource. Do not call this API on a #GSource that you did not create.
the monotonic time at which the source will be ready, 0 for "immediately", -1 for "never"
A variant of g_source_set_name() that does not
duplicate the name, and can only be used with
string literals.
debug name for the source
Decreases the reference count of a source by one. If the resulting reference count is zero the source and associated memory will be destroyed.
Creates a new #GSource structure. The size is specified to
allow creating structures derived from #GSource that contain
additional data. The size passed in must be at least
sizeof (GSource).
The source will not initially be associated with any #GMainContext and must be added to one with g_source_attach() before it will be executed.
structure containing functions that implement the sources behavior.
size of the #GSource structure to create.
Removes the source with the given ID from the default main context. You must use g_source_destroy() for sources added to a non-default main context.
The ID of a #GSource is given by g_source_get_id(), or will be returned by the functions g_source_attach(), g_idle_add(), g_idle_add_full(), g_timeout_add(), g_timeout_add_full(), g_child_watch_add(), g_child_watch_add_full(), g_io_add_watch(), and g_io_add_watch_full().
It is a programmer error to attempt to remove a non-existent source.
More specifically: source IDs can be reissued after a source has been destroyed and therefore it is never valid to use this function with a source ID which may have already been removed. An example is when scheduling an idle to run in another thread with g_idle_add(): the idle may already have run and been removed by the time this function is called on its (now invalid) source ID. This source ID may have been reissued, leading to the operation being performed against the wrong source.
the ID of the source to remove.
Removes a source from the default main loop context given the source functions and user data. If multiple sources exist with the same source functions and user data, only one will be destroyed.
The source_funcs passed to g_source_new()
the user data for the callback
Removes a source from the default main loop context given the user data for the callback. If multiple sources exist with the same user data, only one will be destroyed.
the user_data for the callback.
Sets the name of a source using its ID.
This is a convenience utility to set source names from the return value of g_idle_add(), g_timeout_add(), etc.
It is a programmer error to attempt to set the name of a non-existent source.
More specifically: source IDs can be reissued after a source has been destroyed and therefore it is never valid to use this function with a source ID which may have already been removed. An example is when scheduling an idle to run in another thread with g_idle_add(): the idle may already have run and been removed by the time this function is called on its (now invalid) source ID. This source ID may have been reissued, leading to the operation being performed against the wrong source.
a #GSource ID
debug name for the source
The
GSourcestruct is an opaque data type representing an event source.