Creates a binding between source_property on source and target_property
on target.
Whenever the source_property is changed the target_property is
updated using the same value. For instance:
g_object_bind_property (action, "active", widget, "sensitive", 0);
Will result in the "sensitive" property of the widget #GObject instance to be updated with the same value of the "active" property of the action #GObject instance.
If flags contains %G_BINDING_BIDIRECTIONAL then the binding will be mutual:
if target_property on target changes then the source_property on source
will be updated as well.
The binding will automatically be removed when either the source or the
target instances are finalized. To remove the binding without affecting the
source and the target you can just call g_object_unref() on the returned
#GBinding instance.
Removing the binding by calling g_object_unref() on it must only be done if
the binding, source and target are only used from a single thread and it
is clear that both source and target outlive the binding. Especially it
is not safe to rely on this if the binding, source or target can be
finalized from different threads. Keep another reference to the binding and
use g_binding_unbind() instead to be on the safe side.
A #GObject can have multiple bindings.
the property on source to bind
the target #GObject
the property on target to bind
flags to pass to #GBinding
Creates a binding between source_property on source and target_property
on target, allowing you to set the transformation functions to be used by
the binding.
This function is the language bindings friendly version of g_object_bind_property_full(), using #GClosures instead of function pointers.
the property on source to bind
the target #GObject
the property on target to bind
flags to pass to #GBinding
a #GClosure wrapping the transformation function from the source to the target, or %NULL to use the default
a #GClosure wrapping the transformation function from the target to the source, or %NULL to use the default
Checks if stream is actually pollable. Some classes may implement
#GPollableInputStream but have only certain instances of that class
be pollable. If this method returns %FALSE, then the behavior of
other #GPollableInputStream methods is undefined.
For any given stream, the value returned by this method is constant; a stream cannot switch from pollable to non-pollable or vice versa.
Clears the pending flag on stream.
Closes the stream, releasing resources related to it.
Once the stream is closed, all other operations will return %G_IO_ERROR_CLOSED. Closing a stream multiple times will not return an error.
Streams will be automatically closed when the last reference is dropped, but you might want to call this function to make sure resources are released as early as possible.
Some streams might keep the backing store of the stream (e.g. a file descriptor) open after the stream is closed. See the documentation for the individual stream for details.
On failure the first error that happened will be reported, but the close operation will finish as much as possible. A stream that failed to close will still return %G_IO_ERROR_CLOSED for all operations. Still, it is important to check and report the error to the user.
If cancellable is not %NULL, then the operation 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.
Cancelling a close will still leave the stream closed, but some streams
can use a faster close that doesn't block to e.g. check errors.
optional #GCancellable object, %NULL to ignore.
Requests an asynchronous closes of the stream, releasing resources related to it.
When the operation is finished callback will be called.
You can then call g_input_stream_close_finish() to get the result of the
operation.
For behaviour details see g_input_stream_close().
The asynchronous methods have a default fallback that uses threads to implement asynchronicity, so they are optional for inheriting classes. However, if you override one you must override all.
the [I/O priority][io-priority] of the request
optional cancellable object
callback to call when the request is satisfied
Finishes closing a stream asynchronously, started from g_input_stream_close_async().
a #GAsyncResult.
Creates a #GSource that triggers when stream can be read, or
cancellable is triggered or an error occurs. The callback on the
source is of the #GPollableSourceFunc type.
As with g_pollable_input_stream_is_readable(), it is possible that the stream may not actually be readable even after the source triggers, so you should use g_pollable_input_stream_read_nonblocking() rather than g_input_stream_read() from the callback.
a #GCancellable, or %NULL
This function is intended for #GObject implementations to re-enforce a [floating][floating-ref] object reference. Doing this is seldom required: all #GInitiallyUnowneds are created with a floating reference which usually just needs to be sunken by calling g_object_ref_sink().
Increases the freeze count on object. If the freeze count is
non-zero, the emission of "notify" signals on object is
stopped. The signals are queued until the freeze count is decreased
to zero. Duplicate notifications are squashed so that at most one
#GObject::notify signal is emitted for each property modified while the
object is frozen.
This is necessary for accessors that modify multiple properties to prevent premature notification while the object is still being modified.
Gets a named field from the objects table of associations (see g_object_set_data()).
name of the key for that association
Gets a property of an object.
The value can be:
In general, a copy is made of the property contents and the caller is responsible for freeing the memory by calling g_value_unset().
Note that g_object_get_property() is really intended for language bindings, g_object_get() is much more convenient for C programming.
the name of the property to get
return location for the property value
This function gets back user data pointers stored via g_object_set_qdata().
A #GQuark, naming the user data pointer
Gets n_properties properties for an object.
Obtained properties will be set to values. All properties must be valid.
Warnings will be emitted and undefined behaviour may result if invalid
properties are passed in.
the names of each property to get
the values of each property to get
Checks if an input stream has pending actions.
Checks if an input stream is closed.
Checks whether object has a [floating][floating-ref] reference.
Checks if stream can be read.
Note that some stream types may not be able to implement this 100% reliably, and it is possible that a call to g_input_stream_read() after this returns %TRUE would still block. To guarantee non-blocking behavior, you should always use g_pollable_input_stream_read_nonblocking(), which will return a %G_IO_ERROR_WOULD_BLOCK error rather than blocking.
Emits a "notify" signal for the property property_name on object.
When possible, eg. when signaling a property change from within the class that registered the property, you should use g_object_notify_by_pspec() instead.
Note that emission of the notify signal may be blocked with g_object_freeze_notify(). In this case, the signal emissions are queued and will be emitted (in reverse order) when g_object_thaw_notify() is called.
the name of a property installed on the class of object.
Emits a "notify" signal for the property specified by pspec on object.
This function omits the property name lookup, hence it is faster than g_object_notify().
One way to avoid using g_object_notify() from within the class that registered the properties, and using g_object_notify_by_pspec() instead, is to store the GParamSpec used with g_object_class_install_property() inside a static array, e.g.:
enum
{
PROP_0,
PROP_FOO,
PROP_LAST
};
static GParamSpec *properties[PROP_LAST];
static void
my_object_class_init (MyObjectClass *klass)
{
properties[PROP_FOO] = g_param_spec_int ("foo", "Foo", "The foo",
0, 100,
50,
G_PARAM_READWRITE);
g_object_class_install_property (gobject_class,
PROP_FOO,
properties[PROP_FOO]);
}
and then notify a change on the "foo" property with:
g_object_notify_by_pspec (self, properties[PROP_FOO]);
the #GParamSpec of a property installed on the class of object.
Tries to read count bytes from the stream into the buffer starting at
buffer. Will block during this read.
If count is zero returns zero and does nothing. A value of count
larger than %G_MAXSSIZE will cause a %G_IO_ERROR_INVALID_ARGUMENT error.
On success, the number of bytes read into the buffer is returned.
It is not an error if this is not the same as the requested size, as it
can happen e.g. near the end of a file. Zero is returned on end of file
(or if count is zero), but never otherwise.
The returned buffer is not a nul-terminated string, it can contain nul bytes
at any position, and this function doesn't nul-terminate the buffer.
If cancellable is not %NULL, then the operation 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 an
operation was partially finished when the operation was cancelled the
partial result will be returned, without an error.
On error -1 is returned and error is set accordingly.
optional #GCancellable object, %NULL to ignore.
Tries to read count bytes from the stream into the buffer starting at
buffer. Will block during this read.
This function is similar to g_input_stream_read(), except it tries to read as many bytes as requested, only stopping on an error or end of stream.
On a successful read of count bytes, or if we reached the end of the
stream, %TRUE is returned, and bytes_read is set to the number of bytes
read into buffer.
If there is an error during the operation %FALSE is returned and error
is set to indicate the error status.
As a special exception to the normal conventions for functions that
use #GError, if this function returns %FALSE (and sets error) then
bytes_read will be set to the number of bytes that were successfully
read before the error was encountered. This functionality is only
available from C. If you need it from another language then you must
write your own loop around g_input_stream_read().
optional #GCancellable object, %NULL to ignore.
Request an asynchronous read of count bytes from the stream into the
buffer starting at buffer.
This is the asynchronous equivalent of g_input_stream_read_all().
Call g_input_stream_read_all_finish() to collect the result.
Any outstanding I/O request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is %G_PRIORITY_DEFAULT.
the [I/O priority][io-priority] of the request
optional #GCancellable object, %NULL to ignore
callback to call when the request is satisfied
Finishes an asynchronous stream read operation started with g_input_stream_read_all_async().
As a special exception to the normal conventions for functions that
use #GError, if this function returns %FALSE (and sets error) then
bytes_read will be set to the number of bytes that were successfully
read before the error was encountered. This functionality is only
available from C. If you need it from another language then you must
write your own loop around g_input_stream_read_async().
a #GAsyncResult
Request an asynchronous read of count bytes from the stream into the buffer
starting at buffer. When the operation is finished callback will be called.
You can then call g_input_stream_read_finish() to get the result of the
operation.
During an async request no other sync and async calls are allowed on stream, and will
result in %G_IO_ERROR_PENDING errors.
A value of count larger than %G_MAXSSIZE will cause a %G_IO_ERROR_INVALID_ARGUMENT error.
On success, the number of bytes read into the buffer will be passed to the
callback. It is not an error if this is not the same as the requested size, as it
can happen e.g. near the end of a file, but generally we try to read
as many bytes as requested. Zero is returned on end of file
(or if count is zero), but never otherwise.
Any outstanding i/o request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is %G_PRIORITY_DEFAULT.
The asynchronous methods have a default fallback that uses threads to implement asynchronicity, so they are optional for inheriting classes. However, if you override one you must override all.
the [I/O priority][io-priority] of the request.
optional #GCancellable object, %NULL to ignore.
callback to call when the request is satisfied
Like g_input_stream_read(), this tries to read count bytes from
the stream in a blocking fashion. However, rather than reading into
a user-supplied buffer, this will create a new #GBytes containing
the data that was read. This may be easier to use from language
bindings.
If count is zero, returns a zero-length #GBytes and does nothing. A
value of count larger than %G_MAXSSIZE will cause a
%G_IO_ERROR_INVALID_ARGUMENT error.
On success, a new #GBytes is returned. It is not an error if the
size of this object is not the same as the requested size, as it
can happen e.g. near the end of a file. A zero-length #GBytes is
returned on end of file (or if count is zero), but never
otherwise.
If cancellable is not %NULL, then the operation 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 an
operation was partially finished when the operation was cancelled the
partial result will be returned, without an error.
On error %NULL is returned and error is set accordingly.
maximum number of bytes that will be read from the stream. Common values include 4096 and 8192.
optional #GCancellable object, %NULL to ignore.
Request an asynchronous read of count bytes from the stream into a
new #GBytes. When the operation is finished callback will be
called. You can then call g_input_stream_read_bytes_finish() to get the
result of the operation.
During an async request no other sync and async calls are allowed
on stream, and will result in %G_IO_ERROR_PENDING errors.
A value of count larger than %G_MAXSSIZE will cause a
%G_IO_ERROR_INVALID_ARGUMENT error.
On success, the new #GBytes will be passed to the callback. It is
not an error if this is smaller than the requested size, as it can
happen e.g. near the end of a file, but generally we try to read as
many bytes as requested. Zero is returned on end of file (or if
count is zero), but never otherwise.
Any outstanding I/O request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is %G_PRIORITY_DEFAULT.
the number of bytes that will be read from the stream
the [I/O priority][io-priority] of the request
optional #GCancellable object, %NULL to ignore.
callback to call when the request is satisfied
Finishes an asynchronous stream read-into-#GBytes operation.
a #GAsyncResult.
Finishes an asynchronous stream read operation.
a #GAsyncResult.
Attempts to read up to count bytes from stream into buffer, as
with g_input_stream_read(). If stream is not currently readable,
this will immediately return %G_IO_ERROR_WOULD_BLOCK, and you can
use g_pollable_input_stream_create_source() to create a #GSource
that will be triggered when stream is readable.
Note that since this method never blocks, you cannot actually
use cancellable to cancel it. However, it will return an error
if cancellable has already been cancelled when you call, which
may happen if you call this method after a source triggers due
to having been cancelled.
a #GCancellable, or %NULL
Increase the reference count of object, and possibly remove the
[floating][floating-ref] reference, if object has a floating reference.
In other words, if the object is floating, then this call "assumes ownership" of the floating reference, converting it to a normal reference by clearing the floating flag while leaving the reference count unchanged. If the object is not floating, then this call adds a new normal reference increasing the reference count by one.
Since GLib 2.56, the type of object will be propagated to the return type
under the same conditions as for g_object_ref().
Releases all references to other objects. This can be used to break reference cycles.
This function should only be called from object system implementations.
Each object carries around a table of associations from strings to pointers. This function lets you set an association.
If the object already had an association with that name, the old association will be destroyed.
Internally, the key is converted to a #GQuark using g_quark_from_string().
This means a copy of key is kept permanently (even after object has been
finalized) — so it is recommended to only use a small, bounded set of values
for key in your program, to avoid the #GQuark storage growing unbounded.
name of the key
data to associate with that key
Sets stream to have actions pending. If the pending flag is
already set or stream is closed, it will return %FALSE and set
error.
Sets a property on an object.
the name of the property to set
the value
Tries to skip count bytes from the stream. Will block during the operation.
This is identical to g_input_stream_read(), from a behaviour standpoint, but the bytes that are skipped are not returned to the user. Some streams have an implementation that is more efficient than reading the data.
This function is optional for inherited classes, as the default implementation emulates it using read.
If cancellable is not %NULL, then the operation 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 an
operation was partially finished when the operation was cancelled the
partial result will be returned, without an error.
the number of bytes that will be skipped from the stream
optional #GCancellable object, %NULL to ignore.
Request an asynchronous skip of count bytes from the stream.
When the operation is finished callback will be called.
You can then call g_input_stream_skip_finish() to get the result
of the operation.
During an async request no other sync and async calls are allowed, and will result in %G_IO_ERROR_PENDING errors.
A value of count larger than %G_MAXSSIZE will cause a %G_IO_ERROR_INVALID_ARGUMENT error.
On success, the number of bytes skipped will be passed to the callback.
It is not an error if this is not the same as the requested size, as it
can happen e.g. near the end of a file, but generally we try to skip
as many bytes as requested. Zero is returned on end of file
(or if count is zero), but never otherwise.
Any outstanding i/o request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is %G_PRIORITY_DEFAULT.
The asynchronous methods have a default fallback that uses threads to implement asynchronicity, so they are optional for inheriting classes. However, if you override one, you must override all.
the number of bytes that will be skipped from the stream
the [I/O priority][io-priority] of the request
optional #GCancellable object, %NULL to ignore.
callback to call when the request is satisfied
Finishes a stream skip operation.
a #GAsyncResult.
Remove a specified datum from the object's data associations, without invoking the association's destroy handler.
name of the key
This function gets back user data pointers stored via
g_object_set_qdata() and removes the data from object
without invoking its destroy() function (if any was
set).
Usually, calling this function is only required to update
user data pointers with a destroy notifier, for example:
void
object_add_to_user_list (GObject *object,
const gchar *new_string)
{
// the quark, naming the object data
GQuark quark_string_list = g_quark_from_static_string ("my-string-list");
// retrieve the old string list
GList *list = g_object_steal_qdata (object, quark_string_list);
// prepend new string
list = g_list_prepend (list, g_strdup (new_string));
// this changed 'list', so we need to set it again
g_object_set_qdata_full (object, quark_string_list, list, free_string_list);
}
static void
free_string_list (gpointer data)
{
GList *node, *list = data;
for (node = list; node; node = node->next)
g_free (node->data);
g_list_free (list);
}
Using g_object_get_qdata() in the above example, instead of g_object_steal_qdata() would have left the destroy function set, and thus the partial string list would have been freed upon g_object_set_qdata_full().
A #GQuark, naming the user data pointer
Reverts the effect of a previous call to
g_object_freeze_notify(). The freeze count is decreased on object
and when it reaches zero, queued "notify" signals are emitted.
Duplicate notifications for each property are squashed so that at most one #GObject::notify signal is emitted for each property, in the reverse order in which they have been queued.
It is an error to call this function when the freeze count is zero.
Decreases the reference count of object. When its reference count
drops to 0, the object is finalized (i.e. its memory is freed).
If the pointer to the #GObject may be reused in future (for example, if it is an instance variable of another object), it is recommended to clear the pointer to %NULL rather than retain a dangling pointer to a potentially invalid #GObject instance. Use g_clear_object() for this.
This function essentially limits the life time of the closure to
the life time of the object. That is, when the object is finalized,
the closure is invalidated by calling g_closure_invalidate() on
it, in order to prevent invocations of the closure with a finalized
(nonexisting) object. Also, g_object_ref() and g_object_unref() are
added as marshal guards to the closure, to ensure that an extra
reference count is held on object during invocation of the
closure. Usually, this function will be called on closures that
use this object as closure data.
#GClosure to watch
Find the #GParamSpec with the given name for an
interface. Generally, the interface vtable passed in as g_iface
will be the default vtable from g_type_default_interface_ref(), or,
if you know the interface has already been loaded,
g_type_default_interface_peek().
any interface vtable for the interface, or the default vtable for the interface
name of a property to look up.
Add a property to an interface; this is only useful for interfaces that are added to GObject-derived types. Adding a property to an interface forces all objects classes with that interface to have a compatible property. The compatible property could be a newly created #GParamSpec, but normally g_object_class_override_property() will be used so that the object class only needs to provide an implementation and inherits the property description, default value, bounds, and so forth from the interface property.
This function is meant to be called from the interface's default
vtable initialization function (the class_init member of
#GTypeInfo.) It must not be called after after class_init has
been called for any object types implementing this interface.
If pspec is a floating reference, it will be consumed.
any interface vtable for the interface, or the default vtable for the interface.
the #GParamSpec for the new property
Lists the properties of an interface.Generally, the interface
vtable passed in as g_iface will be the default vtable from
g_type_default_interface_ref(), or, if you know the interface has
already been loaded, g_type_default_interface_peek().
any interface vtable for the interface, or the default vtable for the interface
Creates a new instance of a #GObject subtype and sets its properties.
Construction parameters (see %G_PARAM_CONSTRUCT, %G_PARAM_CONSTRUCT_ONLY) which are not explicitly specified are set to their default values.
the type id of the #GObject subtype to instantiate
an array of #GParameter
#GPollableInputStream is implemented by #GInputStreams that can be polled for readiness to read. This can be used when interfacing with a non-GIO API that expects UNIX-file-descriptor-style asynchronous I/O rather than GIO-style.