Description
This is the asynchronous version of GInitable; it behaves the same
in all ways except that initialization is asynchronous. For more details
see the descriptions on GInitable.
A class may implement both the GInitable and GAsyncInitable interfaces.
Users of objects implementing this are not intended to use the interface
method directly; instead it will be used automatically in various ways.
For C applications you generally just call g_async_initable_new_async()
directly, or indirectly via a foo_thing_new_async() wrapper. This will call
g_async_initable_init_async() under the cover, calling back with NULL and
a set GError on failure.
A typical implementation might look something like this:
Functions
g_async_initable_init_async ()
void
g_async_initable_init_async (GAsyncInitable *initable,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data);
Starts asynchronous initialization of the object implementing the
interface. This must be done before any real use of the object after
initial construction. If the object also implements GInitable you can
optionally call g_initable_init() instead.
This method is intended for language bindings. If writing in C,
g_async_initable_new_async() should typically be used instead.
When the initialization is finished, callback
will be called. You can
then call g_async_initable_init_finish() to get the result of the
initialization.
Implementations may also support cancellation. If cancellable
is not
NULL, then initialization can be cancelled by triggering the cancellable
object from another thread. If the operation was cancelled, the error
G_IO_ERROR_CANCELLED will be returned. If cancellable
is not NULL, and
the object doesn't support cancellable initialization, the error
G_IO_ERROR_NOT_SUPPORTED will be returned.
As with GInitable, if the object is not initialized, or initialization
returns with an error, then all operations on the object except
g_object_ref() and g_object_unref() are considered to be invalid, and
have undefined behaviour. They will often fail with g_critical() or
g_warning(), but this must not be relied on.
Callers should not assume that a class which implements GAsyncInitable can
be initialized multiple times; for more information, see g_initable_init().
If a class explicitly supports being initialized multiple times,
implementation requires yielding all subsequent calls to init_async() on the
results of the first call.
For classes that also support the GInitable interface, the default
implementation of this method will run the g_initable_init() function
in a thread, so if you want to support asynchronous initialization via
threads, just implement the GAsyncInitable interface without overriding
any interface methods.
Since: 2.22
g_async_initable_init_finish ()
gboolean
g_async_initable_init_finish (GAsyncInitable *initable,
GAsyncResult *res,
GError **error);
Finishes asynchronous initialization and returns the result.
See g_async_initable_init_async().
Returns
TRUE if successful. If an error has occurred, this function
will return FALSE and set error
appropriately if present.
Since: 2.22
g_async_initable_new_async ()
void
g_async_initable_new_async (GType object_type,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data,
const gchar *first_property_name,
...);
Helper function for constructing GAsyncInitable object. This is
similar to g_object_new() but also initializes the object asynchronously.
When the initialization is finished, callback
will be called. You can
then call g_async_initable_new_finish() to get the new object and check
for any errors.
Since: 2.22
g_async_initable_new_finish ()
GObject *
g_async_initable_new_finish (GAsyncInitable *initable,
GAsyncResult *res,
GError **error);
Finishes the async construction for the various g_async_initable_new
calls, returning the created object or NULL on error.
Returns
a newly created GObject,
or NULL on error. Free with g_object_unref().
[type GObject.Object][transfer full]
Since: 2.22
g_async_initable_new_valist_async ()
void
g_async_initable_new_valist_async (GType object_type,
const gchar *first_property_name,
va_list var_args,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data);
Helper function for constructing GAsyncInitable object. This is
similar to g_object_new_valist() but also initializes the object
asynchronously.
When the initialization is finished, callback
will be called. You can
then call g_async_initable_new_finish() to get the new object and check
for any errors.
Since: 2.22
g_async_initable_newv_async ()
void
g_async_initable_newv_async (GType object_type,
guint n_parameters,
GParameter *parameters,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data);
g_async_initable_newv_async has been deprecated since version 2.54 and should not be used in newly-written code.
Use g_object_new_with_properties() and
g_async_initable_init_async() instead. See GParameter for more information.
Helper function for constructing GAsyncInitable object. This is
similar to g_object_newv() but also initializes the object asynchronously.
When the initialization is finished, callback
will be called. You can
then call g_async_initable_new_finish() to get the new object and check
for any errors.
Since: 2.22
Types and Values
GAsyncInitable
typedef struct _GAsyncInitable GAsyncInitable;
Interface for asynchronously initializable objects.
Since: 2.22
struct GAsyncInitableIface
struct GAsyncInitableIface {
GTypeInterface g_iface;
/* Virtual Table */
void (* init_async) (GAsyncInitable *initable,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data);
gboolean (* init_finish) (GAsyncInitable *initable,
GAsyncResult *res,
GError **error);
};
Provides an interface for asynchronous initializing object such that
initialization may fail.
Since: 2.22