Gio::IOStream Class Reference

IOStream - Base class for implementing read/write streams. More...

#include <giomm/iostream.h>

Inheritance diagram for Gio::IOStream:

Public Types
enum class	SpliceFlags {   NONE = 0x0 ,   CLOSE_STREAM1 = (1 << 0) ,   CLOSE_STREAM2 = (1 << 1) ,   WAIT_FOR_BOTH = (1 << 2) }
Public Types inherited from Glib::Object
using	DestroyNotify = void(*)(gpointer data)

Public Member Functions
	IOStream (IOStream &&src) noexcept
IOStream &	operator= (IOStream &&src) noexcept
	~IOStream () noexcept override
GIOStream *	gobj ()
	Provides access to the underlying C GObject.
const GIOStream *	gobj () const
	Provides access to the underlying C GObject.
GIOStream *	gobj_copy ()
	Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs.
void	splice_async (const Glib::RefPtr< IOStream > &stream2, const SlotAsyncReady &slot, const Glib::RefPtr< Cancellable > &cancellable, SpliceFlags flags=SpliceFlags::NONE, int io_priority=Glib::PRIORITY_DEFAULT)
	Asyncronously splice the output stream to the input stream of stream2, and splice the output stream of stream2 to the input stream of this stream.
void	splice_async (const Glib::RefPtr< IOStream > &stream2, const SlotAsyncReady &slot, SpliceFlags flags=SpliceFlags::NONE, int io_priority=Glib::PRIORITY_DEFAULT)
	A non-cancellable version of splice_async().
Glib::RefPtr< InputStream >	get_input_stream ()
	Gets the input stream for this object.
Glib::RefPtr< OutputStream >	get_output_stream ()
	Gets the output stream for this object.
bool	close (const Glib::RefPtr< Cancellable > &cancellable)
	Closes the stream, releasing resources related to it.
bool	close ()
	A close() convenience overload.
void	close_async (const SlotAsyncReady &slot, const Glib::RefPtr< Cancellable > &cancellable, int io_priority=Glib::PRIORITY_DEFAULT)
void	close_async (const SlotAsyncReady &slot, int io_priority=Glib::PRIORITY_DEFAULT)
bool	close_finish (const Glib::RefPtr< AsyncResult > &result)
	Closes a stream.
bool	is_closed () const
	Checks if a stream is closed.
bool	has_pending () const
	Checks if a stream has pending actions.
bool	set_pending ()
	Sets stream to have actions pending.
void	clear_pending ()
	Clears the pending flag on stream.
Public Member Functions inherited from Glib::Object
	Object (const Object &)=delete
Object &	operator= (const Object &)=delete
	Object (Object &&src) noexcept
Object &	operator= (Object &&src) noexcept
void *	get_data (const QueryQuark & key)
void	set_data (const Quark & key, void *data)
void	set_data_with_c_callback (const Quark & key, void *data, GDestroyNotify notify)
void	set_data (const Quark & key, void *data, DestroyNotify notify)
	Prefer set_data_with_c_callback() with a callback with C linkage.
void	remove_data (const QueryQuark &quark)
void *	steal_data (const QueryQuark &quark)
Public Member Functions inherited from Glib::ObjectBase
	ObjectBase (const ObjectBase &)=delete
ObjectBase &	operator= (const ObjectBase &)=delete
void	set_property_value (const Glib::ustring & property_name, const Glib::ValueBase & value)
	You probably want to use a specific property_*() accessor method instead.
void	get_property_value (const Glib::ustring & property_name, Glib::ValueBase & value) const
	You probably want to use a specific property_*() accessor method instead.
template<class PropertyType >
void	set_property (const Glib::ustring & property_name, const PropertyType & value)
	You probably want to use a specific property_*() accessor method instead.
template<class PropertyType >
void	get_property (const Glib::ustring & property_name, PropertyType & value) const
	You probably want to use a specific property_*() accessor method instead.
template<class PropertyType >
PropertyType	get_property (const Glib::ustring & property_name) const
	You probably want to use a specific property_*() accessor method instead.
sigc::connection	connect_property_changed (const Glib::ustring & property_name, const sigc::slot< void()> &slot)
	You can use the signal_changed() signal of the property proxy instead.
sigc::connection	connect_property_changed (const Glib::ustring & property_name, sigc::slot< void()> &&slot)
	You can use the signal_changed() signal of the property proxy instead.
void	freeze_notify ()
	Increases the freeze count on object.
void	thaw_notify ()
	Reverts the effect of a previous call to freeze_notify().
virtual void	reference () const
	Increment the reference count for this object.
virtual void	unreference () const
	Decrement the reference count for this object.
GObject *	gobj ()
	Provides access to the underlying C GObject.
const GObject *	gobj () const
	Provides access to the underlying C GObject.
GObject *	gobj_copy () const
	Give a ref-ed copy to someone. Use for direct struct access.

Static Public Member Functions
static GType	get_type ()
	Get the GType for this class, for use with the underlying GObject type system.
static bool	splice_finish (const Glib::RefPtr< AsyncResult > &result)
	Finishes an asynchronous io stream splice operation.

Related Symbols
(Note that these are not member symbols.)
Glib::RefPtr< Gio::IOStream >	wrap (GIOStream *object, bool take_copy=false)
	A Glib::wrap() method for this object.
Related Symbols inherited from Glib::Object
Glib::RefPtr< Glib::Object >	wrap (GObject *object, bool take_copy=false)

Additional Inherited Members
Protected Member Functions inherited from Glib::Object
	Object ()
	Object (const Glib::ConstructParams &construct_params)
	Object (GObject *castitem)
	~Object () noexcept override
Protected Member Functions inherited from Glib::ObjectBase
	ObjectBase ()
	This default constructor is called implicitly from the constructor of user-derived classes, even if, for instance, Gtk::Button calls a different ObjectBase constructor.
	ObjectBase (const char *custom_type_name)
	A derived constructor always overrides this choice.
	ObjectBase (const std::type_info &custom_type_info)
	This constructor is a special feature to allow creation of derived types on the fly, without having to use g_object_new() manually.
	ObjectBase (ObjectBase &&src) noexcept
ObjectBase &	operator= (ObjectBase &&src) noexcept
virtual	~ObjectBase () noexcept=0
void	initialize (GObject *castitem)
void	initialize_move (GObject *castitem, Glib::ObjectBase *previous_wrapper)

Detailed Description

IOStream - Base class for implementing read/write streams.

IOStream represents an object that has both read and write streams. Generally the two streams acts as separate input and output streams, but they share some common resources and state. For instance, for seekable streams they may use the same position in both streams.

Examples of IOStream objects are SocketConnection which represents a two-way network connection, and FileIOStream which represent a file handle opened in read-write mode.

To do the actual reading and writing you need to get the substreams with get_input_stream() and get_output_stream().

The IOStream object owns the input and the output streams, not the other way around, so keeping the substreams alive will not keep the IOStream object alive. If the IOStream object is freed it will be closed, thus closing the substream, so even if the substreams stay alive they will always just return a Gio::IO_ERROR_CLOSED for all operations.

To close a stream use close() which will close the common stream object and also the individual substreams. You can also close the substreams themselves. In most cases this only marks the substream as closed, so further I/O on it fails. However, some streams may support "half-closed" states where one direction of the stream is actually shut down.

Since glibmm 2.22:

Member Enumeration Documentation

SpliceFlags

enum class Gio::IOStream::SpliceFlags

strong

Enumerator
NONE	Do not close either stream.
CLOSE_STREAM1	Close the first stream after the splice.
CLOSE_STREAM2	Close the second stream after the splice.
WAIT_FOR_BOTH	Wait for both splice operations to finish before calling the callback.

Constructor & Destructor Documentation

IOStream()

Gio::IOStream::IOStream ( IOStream &&  src )

noexcept

~IOStream()

Gio::IOStream::~IOStream ( )

overridenoexcept

Member Function Documentation

clear_pending()

void Gio::IOStream::clear_pending

(

)

Clears the pending flag on stream.

Since glibmm 2.22:

close() [1/2]

bool Gio::IOStream::close

(

)

A close() convenience overload.

close() [2/2]

bool Gio::IOStream::close

(

const Glib::RefPtr< Cancellable > &

cancellable

)

Closes the stream, releasing resources related to it.

This will also close the individual input and output streams, if they are not already closed.

Once the stream is closed, all other operations will return Gio::Error::CLOSED. Closing a stream multiple times will not return an error.

Closing a stream will automatically flush any outstanding buffers in the stream.

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 Gio::Error::CLOSED for all operations. Still, it is important to check and report the error to the user, otherwise there might be a loss of data as all data might not be written.

If cancellable is not nullptr, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error Gio::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.

The default implementation of this method just calls close on the individual input/output streams.

Since glibmm 2.22:

Parameters

cancellable

Optional Cancellable object, nullptr to ignore.

Returns

true on success, false on failure.

Exceptions

Glib::Error

close_async() [1/2]

void Gio::IOStream::close_async	(	const SlotAsyncReady &	slot,
		const Glib::RefPtr< Cancellable > &	cancellable,
		int	io_priority = Glib::PRIORITY_DEFAULT
	)

close_async() [2/2]

void Gio::IOStream::close_async	(	const SlotAsyncReady &	slot,
		int	io_priority = Glib::PRIORITY_DEFAULT
	)

close_finish()

bool Gio::IOStream::close_finish

(

const Glib::RefPtr< AsyncResult > &

result

)

Closes a stream.

Since glibmm 2.22:

Parameters

result

A AsyncResult.

Returns

true if stream was successfully closed, false otherwise.

Exceptions

Glib::Error

get_input_stream()

Glib::RefPtr< InputStream > Gio::IOStream::get_input_stream

(

)

Gets the input stream for this object.

This is used for reading.

Since glibmm 2.22:

Returns

A InputStream, owned by the IOStream. Do not free.

get_output_stream()

Glib::RefPtr< OutputStream > Gio::IOStream::get_output_stream

(

)

Gets the output stream for this object.

This is used for writing.

Since glibmm 2.22:

Returns

A OutputStream, owned by the IOStream. Do not free.

get_type()

static GType Gio::IOStream::get_type ( )

static

Get the GType for this class, for use with the underlying GObject type system.

gobj() [1/2]

GIOStream * Gio::IOStream::gobj ( )

inline

Provides access to the underlying C GObject.

gobj() [2/2]

const GIOStream * Gio::IOStream::gobj ( ) const

inline

Provides access to the underlying C GObject.

gobj_copy()

GIOStream * Gio::IOStream::gobj_copy

(

)

Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs.

has_pending()

bool Gio::IOStream::has_pending

(

)

const

Checks if a stream has pending actions.

Since glibmm 2.22:

Returns

true if stream has pending actions.

is_closed()

bool Gio::IOStream::is_closed

(

)

const

Checks if a stream is closed.

Since glibmm 2.22:

Returns

true if the stream is closed.

operator=()

IOStream & Gio::IOStream::operator= ( IOStream &&  src )

noexcept

set_pending()

bool Gio::IOStream::set_pending

(

)

Sets stream to have actions pending.

If the pending flag is already set or stream is closed, it will return false and set error.

Since glibmm 2.22:

Returns

true if pending was previously unset and is now set.

Exceptions

Glib::Error

splice_async() [1/2]

void Gio::IOStream::splice_async	(	const Glib::RefPtr< IOStream > &	stream2,
		const SlotAsyncReady &	slot,
		const Glib::RefPtr< Cancellable > &	cancellable,
		SpliceFlags	flags = SpliceFlags::NONE,
		int	io_priority = Glib::PRIORITY_DEFAULT
	)

Asyncronously splice the output stream to the input stream of stream2, and splice the output stream of stream2 to the input stream of this stream.

When the operation is finished slot will be called. You can then call splice_finish() to get the result of the operation.

Parameters

stream2	The second IOStream.
slot	A SlotAsyncReady slot.
cancellable	A Cancellable object.
flags	A set of SpliceFlags.
io_priority	The io priority of the request.

Since glibmm 2.34:

splice_async() [2/2]

void Gio::IOStream::splice_async	(	const Glib::RefPtr< IOStream > &	stream2,
		const SlotAsyncReady &	slot,
		SpliceFlags	flags = SpliceFlags::NONE,
		int	io_priority = Glib::PRIORITY_DEFAULT
	)

A non-cancellable version of splice_async().

splice_finish()

static bool Gio::IOStream::splice_finish ( const Glib::RefPtr< AsyncResult > &  result )

static

Finishes an asynchronous io stream splice operation.

Since glibmm 2.28:

Parameters

result

A AsyncResult.

Returns

true on success, false otherwise.

Exceptions

Glib::Error

Friends And Related Symbol Documentation

wrap()

Glib::RefPtr< Gio::IOStream > wrap ( GIOStream *  object, bool  take_copy = false  )

related

A Glib::wrap() method for this object.

Parameters

object	The C instance.
take_copy	False if the result should take ownership of the C instance. True if it should take a new copy or ref.

Returns

A C++ instance that wraps this C instance.