Gio::OutputStream Class Reference
Stream Classes

Base class for implementing streaming output. More...

`#include <giomm/outputstream.h>`

Inheritance diagram for Gio::OutputStream:
[legend]

## Public Member Functions

| OutputStream (OutputStream&& src) noexcept
OutputStream& | operator= (OutputStream&& src) noexcept
| ~OutputStream () noexcept override
GOutputStream* | gobj ()
| Provides access to the underlying C GObject. More...
const GOutputStream* | gobj () const
| Provides access to the underlying C GObject. More...
GOutputStream* | gobj_copy ()
| Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs. More...
gssize | write (const void* buffer, gsize count, const Glib::RefPtr< Cancellable >& cancellable)
| Tries to write count bytes from buffer into the stream. More...
gssize | write (const void* buffer, gsize count)
| A write() convenience overload. More...
gssize | write (const std::string& buffer, const Glib::RefPtr< Cancellable >& cancellable)
| Tries to write count bytes from buffer into the stream. More...
gssize | write (const std::string& buffer)
| Tries to write count bytes from buffer into the stream. More...
bool | write_all (const void* buffer, gsize count, gsize& bytes_written, const Glib::RefPtr< Cancellable >& cancellable)
| Tries to write count bytes from buffer into the stream. More...
bool | write_all (const void* buffer, gsize count, gsize& bytes_written)
| A write_all() convenience overload. More...
bool | write_all (const std::string& buffer, gsize& bytes_written, const Glib::RefPtr< Cancellable >& cancellable)
| Tries to write count bytes from buffer into the stream. More...
bool | write_all (const std::string& buffer, gsize& bytes_written)
| Tries to write count bytes from buffer into the stream. More...
gssize | write_bytes (const Glib::RefPtr< const Glib::Bytes >& bytes, const Glib::RefPtr< Cancellable >& cancellable)
| A wrapper function for g_output_stream_write() which takes a Bytes as input. More...
gssize | write_bytes (const Glib::RefPtr< const Glib::Bytes >& bytes)
| A write_bytes() convenience overload. More...
void | write_bytes_async (const Glib::RefPtr< const Glib::Bytes >& bytes, const SlotAsyncReady& slot, const Glib::RefPtr< Cancellable >& cancellable, int io_priority=Glib::PRIORITY_DEFAULT)
| Request an asynchronous write of the data in bytes to the stream. More...
void | write_bytes_async (const Glib::RefPtr< const Glib::Bytes >& bytes, const SlotAsyncReady& slot, int io_priority=Glib::PRIORITY_DEFAULT)
| Request an asynchronous write of the data in bytes to the stream. More...
gssize | write_bytes_finish (const Glib::RefPtr< AsyncResult >& result)
| Finishes a stream write-from-Bytes operation. More...
gssize | splice (const Glib::RefPtr< InputStream >& source, const Glib::RefPtr< Cancellable >& cancellable, OutputStreamSpliceFlags flags=OUTPUT_STREAM_SPLICE_NONE)
| Splices an input stream into an output stream. More...
gssize | splice (const Glib::RefPtr< InputStream >& source, OutputStreamSpliceFlags flags=OUTPUT_STREAM_SPLICE_NONE)
| Splices an input stream into an output stream. More...
bool | flush (const Glib::RefPtr< Cancellable >& cancellable)
| Flushed any outstanding buffers in the stream. More...
bool | flush ()
| A flush() convenience overload. More...
bool | close (const Glib::RefPtr< Cancellable >& cancellable)
| Closes the stream, releasing resources related to it. More...
bool | close ()
| A close() convenience overload. More...
void | write_async (const void* buffer, gsize count, const SlotAsyncReady& slot, const Glib::RefPtr< Cancellable >& cancellable, int io_priority=Glib::PRIORITY_DEFAULT)
| Request an asynchronous write of count bytes from buffer into the stream. More...
void | write_async (const void* buffer, gsize count, const SlotAsyncReady& slot, int io_priority=Glib::PRIORITY_DEFAULT)
| Request an asynchronous write of count bytes from buffer into the stream. More...
gssize | write_finish (const Glib::RefPtr< AsyncResult >& result)
| Finishes a stream write operation. More...
void | write_all_async (const void* buffer, gsize count, const SlotAsyncReady& slot, const Glib::RefPtr< Cancellable >& cancellable, int io_priority=Glib::PRIORITY_DEFAULT)
| Request an asynchronous write of count bytes from buffer into the stream. More...
void | write_all_async (const void* buffer, gsize count, const SlotAsyncReady& slot, int io_priority=Glib::PRIORITY_DEFAULT)
| Request an asynchronous write of count bytes from buffer into the stream. More...
bool | write_all_finish (const Glib::RefPtr< AsyncResult >& result, gsize& bytes_written)
| Finishes an asynchronous stream write operation started with g_output_stream_write_all_async(). More...
void | splice_async (const Glib::RefPtr< InputStream >& source, const SlotAsyncReady& slot, const Glib::RefPtr< Cancellable >& cancellable, OutputStreamSpliceFlags flags=OUTPUT_STREAM_SPLICE_NONE, int io_priority=Glib::PRIORITY_DEFAULT)
| Splices a stream asynchronously. More...
void | splice_async (const Glib::RefPtr< InputStream >& source, const SlotAsyncReady& slot, OutputStreamSpliceFlags flags=OUTPUT_STREAM_SPLICE_NONE, int io_priority=Glib::PRIORITY_DEFAULT)
| Splices a stream asynchronously. More...
gssize | splice_finish (const Glib::RefPtr< AsyncResult >& result)
| Finishes an asynchronous stream splice operation. More...
void | flush_async (const SlotAsyncReady& slot, const Glib::RefPtr< Cancellable >& cancellable, int io_priority=Glib::PRIORITY_DEFAULT)
| Flushes a stream asynchronously. More...
void | flush_async (const SlotAsyncReady& slot, int io_priority=Glib::PRIORITY_DEFAULT)
| Flushes a stream asynchronously. More...
bool | flush_finish (const Glib::RefPtr< AsyncResult >& result)
| Finishes flushing an output stream. More...
void | close_async (const SlotAsyncReady& slot, const Glib::RefPtr< Cancellable >& cancellable, int io_priority=Glib::PRIORITY_DEFAULT)
| Requests an asynchronous close of the stream, releasing resources related to it. More...
void | close_async (const SlotAsyncReady& slot, int io_priority=Glib::PRIORITY_DEFAULT)
| Requests an asynchronous close of the stream, releasing resources related to it. More...
bool | close_finish (const Glib::RefPtr< AsyncResult >& result)
| Closes an output stream. More...
bool | is_closed () const
| Checks if an output stream has already been closed. More...
bool | is_closing () const
| Checks if an output stream is being closed. More...
bool | has_pending () const
| Checks if an output stream has pending actions. More...
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 (const Quark& key, void* data, DestroyNotify notify)
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. More...
void | get_property_value (const Glib::ustring& property_name, Glib::ValueBase& value) const
| You probably want to use a specific property_*() accessor method instead. More...
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. More...
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. More...
void | 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. More...
void | connect_property_changed (const Glib::ustring& property_name, sigc::slot< void >&& slot)
| You can use the signal_changed() signal of the property proxy instead. More...
sigc::connection | connect_property_changed_with_return (const Glib::ustring& property_name, const sigc::slot< void >& slot)
| You can use the signal_changed() signal of the property proxy instead. More...
sigc::connection | connect_property_changed_with_return (const Glib::ustring& property_name, sigc::slot< void >&& slot)
| You can use the signal_changed() signal of the property proxy instead. More...
void | freeze_notify ()
| Increases the freeze count on object. More...
void | thaw_notify ()
| Reverts the effect of a previous call to freeze_notify(). More...
virtual void | reference () const
| Increment the reference count for this object. More...
virtual void | unreference () const
| Decrement the reference count for this object. More...
GObject* | gobj ()
| Provides access to the underlying C GObject. More...
const GObject* | gobj () const
| Provides access to the underlying C GObject. More...
GObject* | gobj_copy () const
| Give a ref-ed copy to someone. Use for direct struct access. More...
Public Member Functions inherited from sigc::trackable
| trackable () noexcept
| trackable (const trackable &src) noexcept
| trackable (trackable &&src)
| ~trackable ()
void | add_destroy_notify_callback (void *data, func_destroy_notify func) const
void | notify_callbacks ()
trackable & | operator= (const trackable &src)
trackable & | operator= (trackable &&src)
void | remove_destroy_notify_callback (void *data) const

## Static Public Member Functions

static GType | get_type ()
| Get the GType for this class, for use with the underlying GObject type system. More...

## Protected Member Functions

| OutputStream ()
bool | set_pending ()
| Sets stream to have actions pending. More...
void | clear_pending ()
| Clears the pending flag on stream. More...
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. More...
| ObjectBase (const char* custom_type_name)
| A derived constructor always overrides this choice. More...
| 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. More...
| 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)

## Related Functions

(Note that these are not member functions.)
Glib::RefPtr< Gio::OutputStream > | wrap (GOutputStream* object, bool take_copy=false)
| A Glib::wrap() method for this object. More...
Related Functions inherited from Glib::Object
Glib::RefPtr< Glib::Object > | wrap (GObject* object, bool take_copy=false)

## Additional Inherited Members

Public Types inherited from Glib::Object
using | DestroyNotify = void(*)(gpointer data)
Public Types inherited from sigc::trackable
typedef internal::func_destroy_notify | func_destroy_notify

## Detailed Description

Base class for implementing streaming output.

Since glibmm 2.16:

## Constructor & Destructor Documentation

## OutputStream() [1/2]

Gio::OutputStream::OutputStream | ( | OutputStream&& | src | ) |

noexcept

## ~OutputStream()

Gio::OutputStream::~OutputStream | ( |  | ) |

override noexcept

## OutputStream() [2/2]

Gio::OutputStream::OutputStream | ( |  | ) |

protected

## Member Function Documentation

## clear_pending()

void Gio::OutputStream::clear_pending | ( |  | ) |

protected

Clears the pending flag on stream.

Since glibmm 2.50:

## close() [1/2]

bool Gio::OutputStream::close | ( | const Glib::RefPtr< Cancellable >& | cancellable | ) |

Closes the stream, releasing resources related to it.

Once the stream is closed, all other operations will throw a Gio::Error with CLOSED. Closing a stream multiple times will not cause an error to be thrown.

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 throw a Gio::Error with 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.

The operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, a Gio::Error will be thrown with CANCELLED. Cancelling a close will still leave the stream closed, but there some streams can use a faster close that doesn't block to e.g. check errors. On cancellation (as with any error) there is no guarantee that all written data will reach the target.

Parameters

  cancellable | Cancellable object.

Returns
  `true` on success, `false` on failure.

Exceptions

  Glib::Error |

## close() [2/2]

bool Gio::OutputStream::close | ( |  | ) |

A close() convenience overload.

## close_async() [1/2]

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

Requests an asynchronous close of the stream, releasing resources related to it.

When the operation is finished the slot will be called, giving the results. You can then call close_finish() to get the result of the operation. For behaviour details see close().

The asyncronous 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.

Parameters

  slot | Callback slot to call when the request is satisfied.
  cancellable | Cancellable object.
  io_priority | The io priority of the request.

## close_async() [2/2]

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

Requests an asynchronous close of the stream, releasing resources related to it.

When the operation is finished the slot will be called, giving the results. You can then call close_finish() to get the result of the operation. For behaviour details see close().

The asyncronous 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.

Parameters

  slot | Callback slot to call when the request is satisfied.
  io_priority | The io priority of the request.

## close_finish()

bool Gio::OutputStream::close_finish | ( | const Glib::RefPtr< AsyncResult >& | result | ) |

Closes an output stream.

Parameters

  result | A AsyncResult.

Returns
  `true` if stream was successfully closed, `false` otherwise.

Exceptions

  Glib::Error |

## flush() [1/2]

bool Gio::OutputStream::flush | ( | const Glib::RefPtr< Cancellable >& | cancellable | ) |

Flushed any outstanding buffers in the stream.

Will block during the operation. Closing the stream will implicitly cause a flush.

This function is optional for inherited classes.

The operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, a Gio::Error will be thrown with CANCELLED.

Parameters

  cancellable | Cancellable object.

Returns
  `true` on success, `false` on error.

Exceptions

  Glib::Error |

## flush() [2/2]

bool Gio::OutputStream::flush | ( |  | ) |

A flush() convenience overload.

## flush_async() [1/2]

void Gio::OutputStream::flush_async | ( | const SlotAsyncReady& | slot,
|  | const Glib::RefPtr< Cancellable >& | cancellable,
|  | int | io_priority = `Glib::PRIORITY_DEFAULT`
| ) |  |

Flushes a stream asynchronously.

When the operation is finished the slot will be called, giving the results. You can then call flush_finish() to get the result of the operation. For behaviour details see flush().

Parameters

  slot | Callback slot to call when the request is satisfied.
  cancellable | Cancellable object.
  io_priority | The io priority of the request.

## flush_async() [2/2]

void Gio::OutputStream::flush_async | ( | const SlotAsyncReady& | slot,
|  | int | io_priority = `Glib::PRIORITY_DEFAULT`
| ) |  |

Flushes a stream asynchronously.

When the operation is finished the slot will be called, giving the results. You can then call flush_finish() to get the result of the operation. For behaviour details see flush().

Parameters

  slot | Callback slot to call when the request is satisfied.
  io_priority | The io priority of the request.

## flush_finish()

bool Gio::OutputStream::flush_finish | ( | const Glib::RefPtr< AsyncResult >& | result | ) |

Finishes flushing an output stream.

Parameters

  result | A GAsyncResult.

Returns
  `true` if flush operation succeeded, `false` otherwise.

Exceptions

  Glib::Error |

## get_type()

static GType Gio::OutputStream::get_type | ( |  | ) |

static

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

## gobj() [1/2]

GOutputStream* Gio::OutputStream::gobj | ( |  | ) |

inline

Provides access to the underlying C GObject.

## gobj() [2/2]

const GOutputStream* Gio::OutputStream::gobj | ( |  | ) | const

inline

Provides access to the underlying C GObject.

## gobj_copy()

GOutputStream* Gio::OutputStream::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::OutputStream::has_pending | ( |  | ) | const

Checks if an output stream has pending actions.

Since glibmm 2.50:

Returns
  `true` if stream has pending actions.

## is_closed()

bool Gio::OutputStream::is_closed | ( |  | ) | const

Checks if an output stream has already been closed.

Since glibmm 2.50:

Returns
  `true` if stream is closed. `false` otherwise.

## is_closing()

bool Gio::OutputStream::is_closing | ( |  | ) | const

Checks if an output stream is being closed.

This can be used inside e.g. a flush implementation to see if the flush (or other i/o operation) is called from within the closing operation.

Since glibmm 2.50:

Returns
  `true` if stream is being closed. `false` otherwise.

## operator=()

OutputStream& Gio::OutputStream::operator= | ( | OutputStream&& | src | ) |

noexcept

## set_pending()

bool Gio::OutputStream::set_pending | ( |  | ) |

protected

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 2.50:

Returns
  `true` if pending was previously unset and is now set.

Exceptions

  Glib::Error |

## splice() [1/2]

gssize Gio::OutputStream::splice | ( | const Glib::RefPtr< InputStream >& | source,
|  | const Glib::RefPtr< Cancellable >& | cancellable,
|  | OutputStreamSpliceFlags | flags = `OUTPUT_STREAM_SPLICE_NONE`
| ) |  |

Splices an input stream into an output stream.

Parameters

  source | An InputStream.
  flags | A set of OutputStreamSpliceFlags.
  cancellable | A Cancellable object. ignore.

Returns
  A #gssize containing the size of the data spliced.

## splice() [2/2]

gssize Gio::OutputStream::splice | ( | const Glib::RefPtr< InputStream >& | source,
|  | OutputStreamSpliceFlags | flags = `OUTPUT_STREAM_SPLICE_NONE`
| ) |  |

Splices an input stream into an output stream.

Parameters

  source | An InputStream.
  flags | A set of OutputStreamSpliceFlags. ignore.

Returns
  A #gssize containing the size of the data spliced.

## splice_async() [1/2]

void Gio::OutputStream::splice_async | ( | const Glib::RefPtr< InputStream >& | source,
|  | const SlotAsyncReady& | slot,
|  | const Glib::RefPtr< Cancellable >& | cancellable,
|  | OutputStreamSpliceFlags | flags = `OUTPUT_STREAM_SPLICE_NONE`,
|  | int | io_priority = `Glib::PRIORITY_DEFAULT`
| ) |  |

Splices a stream asynchronously.

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

For the synchronous, blocking version of this function, see splice().

Parameters

  source | An InputStream.
  slot | Callback slot to call when the request is satisfied.
  cancellable | Cancellable object.
  flags | A set of OutputStreamSpliceFlags.
  io_priority | The io priority of the request.

## splice_async() [2/2]

void Gio::OutputStream::splice_async | ( | const Glib::RefPtr< InputStream >& | source,
|  | const SlotAsyncReady& | slot,
|  | OutputStreamSpliceFlags | flags = `OUTPUT_STREAM_SPLICE_NONE`,
|  | int | io_priority = `Glib::PRIORITY_DEFAULT`
| ) |  |

Splices a stream asynchronously.

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

For the synchronous, blocking version of this function, see splice().

Parameters

  source | An InputStream.
  slot | Callback slot to call when the request is satisfied.
  flags | A set of OutputStreamSpliceFlags.
  io_priority | The io priority of the request.

## splice_finish()

gssize Gio::OutputStream::splice_finish | ( | const Glib::RefPtr< AsyncResult >& | result | ) |

Finishes an asynchronous stream splice operation.

Parameters

  result | A AsyncResult.

Returns
  A #gssize of the number of bytes spliced. Note that if the number of bytes spliced is greater than G_MAXSSIZE, then that will be returned, and there is no way to determine the actual number of bytes spliced.

Exceptions

  Glib::Error |

## write() [1/4]

gssize Gio::OutputStream::write | ( | const void * | buffer,
|  | gsize | count,
|  | const Glib::RefPtr< Cancellable >& | cancellable
| ) |  |

Tries to write count bytes from buffer into the stream.

Will block during the operation.

If count is zero returns zero and does nothing. A value of count larger than G_MAXSSIZE will cause a Gio::Error with INVALID_ARGUMENT to be thrown.

On success, the number of bytes written to the stream is returned. It is not an error if this is not the same as the requested size, as it can happen e.g. on a partial i/o error, or if there is not enough storage in the stream. All writes either block until at least one byte is written, so zero is never returned (unless count is zero).

The operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, a Gio::Error will be thrown with CANCELLED. If an operation was partially finished when the operation was cancelled the partial result will be returned, without an error.

Parameters

  buffer | The buffer containing the data to write.
  count | The number of bytes to write.
  cancellable | Cancellable object.

Returns
  Number of bytes written, or -1 on error.

Exceptions

  Glib::Error |

## write() [2/4]

gssize Gio::OutputStream::write | ( | const void * | buffer,
|  | gsize | count
| ) |  |

A write() convenience overload.

## write() [3/4]

gssize Gio::OutputStream::write | ( | const std::string & | buffer,
|  | const Glib::RefPtr< Cancellable >& | cancellable
| ) |  |

Tries to write count bytes from buffer into the stream.

Will block during the operation.

If count is zero returns zero and does nothing. A value of count larger than MAXSSIZE will cause a Gio::Error with INVALID_ARGUMENT to be thrown.

On success, the number of bytes written to the stream is returned. It is not an error if this is not the same as the requested size, as it can happen e.g. on a partial i/o error, or if the there is not enough storage in the stream. All writes either block until at least one byte is written, so zero is never returned (unless count is zero).

On error -1 is returned.

Parameters

  buffer | The buffer containing the data to write.
  cancellable | Cancellable object.

Returns
  Number of bytes written, or -1 on error.

## write() [4/4]

gssize Gio::OutputStream::write | ( | const std::string & | buffer | ) |

Tries to write count bytes from buffer into the stream.

Will block during the operation.

If string that is larger than MAXSSIZE bytes will cause a Gio::Error with INVALID_ARGUMENT to be thrown.

On success, the number of bytes written to the stream is returned. It is not an error if this is not the same as the requested size, as it can happen e.g. on a partial i/o error, or if the there is not enough storage in the stream. All writes either block until at least one byte is written, so zero is never returned (unless count is zero).

On error -1 is returned.

Parameters

  buffer | The buffer containing the data to write.

Returns
  Number of bytes written, or -1 on error.

## write_all() [1/4]

bool Gio::OutputStream::write_all | ( | const void * | buffer,
|  | gsize | count,
|  | gsize & | bytes_written,
|  | const Glib::RefPtr< Cancellable >& | cancellable
| ) |  |

Tries to write count bytes from buffer into the stream.

Will block during the operation.

This function is similar to g_output_stream_write(), except it tries to write as many bytes as requested, only stopping on an error.

On a successful write of count bytes, `true` is returned, and bytes_written is set to count.

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 Error, if this function returns `false` (and sets error) then bytes_written will be set to the number of bytes that were successfully written 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_output_stream_write().

Parameters

  buffer | The buffer containing the data to write.
  count | The number of bytes to write.
  bytes_written | Location to store the number of bytes that was written to the stream.
  cancellable | Optional Cancellable object, `nullptr` to ignore.

Returns
  `true` on success, `false` if there was an error.

Exceptions

  Glib::Error |

## write_all() [2/4]

bool Gio::OutputStream::write_all | ( | const void * | buffer,
|  | gsize | count,
|  | gsize & | bytes_written
| ) |  |

A write_all() convenience overload.

## write_all() [3/4]

bool Gio::OutputStream::write_all | ( | const std::string & | buffer,
|  | gsize & | bytes_written,
|  | const Glib::RefPtr< Cancellable >& | cancellable
| ) |  |

Tries to write count bytes from buffer into the stream.

Will block during the operation.

This function is similar to write(), except it tries to write as many bytes as requested, only stopping on an error.

On a successful write of count bytes, `true` is returned, and bytes_written is set to count .

If there is an error during the operation `false` is returned and error is set to indicate the error status, bytes_written is updated to contain the number of bytes written into the stream before the error occured.

Parameters

  buffer | The buffer containing the data to write.
  bytes_written | Location to store the number of bytes that was written to the stream.
  cancellable | Cancellable object.

Returns
  `true` on success, `false` if there was an error.

## write_all() [4/4]

bool Gio::OutputStream::write_all | ( | const std::string & | buffer,
|  | gsize & | bytes_written
| ) |  |

Tries to write count bytes from buffer into the stream.

Will block during the operation.

This function is similar to write(), except it tries to write as many bytes as requested, only stopping on an error.

On a successful write of count bytes, `true` is returned, and bytes_written is set to count .

If there is an error during the operation `false` is returned and error is set to indicate the error status, bytes_written is updated to contain the number of bytes written into the stream before the error occured.

Parameters

  buffer | The buffer containing the data to write.
  bytes_written | Location to store the number of bytes that was written to the stream.

Returns
  `true` on success, `false` if there was an error.

## write_all_async() [1/2]

void Gio::OutputStream::write_all_async | ( | const void * | buffer,
|  | gsize | count,
|  | const SlotAsyncReady& | slot,
|  | const Glib::RefPtr< Cancellable >& | cancellable,
|  | int | io_priority = `Glib::PRIORITY_DEFAULT`
| ) |  |

Request an asynchronous write of count bytes from buffer into the stream.

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

This is the asynchronous version of write_all().

During an async request no other sync and async calls are allowed, and will result in Gio::Error with PENDING being thrown.

A value of count larger than MAXSSIZE will cause a Gio::Error with INVALID_ARGUMENT to be thrown.

On success, the number of bytes written will be passed to the callback slot. It is not an error if this is not the same as the requested size, as it can happen e.g. on a partial I/O error, but generally we try to write as many bytes as requested.

Any outstanding I/O request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is Glib::PRIORITY_DEFAULT.

The asyncronous 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.

For the synchronous, blocking version of this function, see write().

Note that no copy of buffer will be made, so it must stay valid until slot is called.

Parameters

  buffer | The buffer containing the data to write.
  count | The number of bytes to write
  slot | Callback slot to call when the request is satisfied.
  cancellable | Cancellable object.
  io_priority | The io priority of the request.

## write_all_async() [2/2]

void Gio::OutputStream::write_all_async | ( | const void * | buffer,
|  | gsize | count,
|  | const SlotAsyncReady& | slot,
|  | int | io_priority = `Glib::PRIORITY_DEFAULT`
| ) |  |

Request an asynchronous write of count bytes from buffer into the stream.

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

This is the asynchronous version of write_all().

During an async request no other sync and async calls are allowed, and will result in Gio::Error with PENDING being thrown.

A value of count larger than MAXSSIZE will cause a Gio::Error with INVALID_ARGUMENT to be thrown.

On success, the number of bytes written will be passed to the callback slot. It is not an error if this is not the same as the requested size, as it can happen e.g. on a partial I/O error, but generally we try to write as many bytes as requested.

Any outstanding I/O request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is Glib::PRIORITY_DEFAULT.

The asyncronous 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.

For the synchronous, blocking version of this function, see write().

Note that no copy of buffer will be made, so it must stay valid until slot is called.

Parameters

  buffer | The buffer containing the data to write.
  count | The number of bytes to write
  slot | Callback slot to call when the request is satisfied.
  io_priority | The io priority of the request.

## write_all_finish()

bool Gio::OutputStream::write_all_finish | ( | const Glib::RefPtr< AsyncResult >& | result,
|  | gsize & | bytes_written
| ) |  |

Finishes an asynchronous stream write operation started with g_output_stream_write_all_async().

As a special exception to the normal conventions for functions that use Error, if this function returns `false` (and sets error) then bytes_written will be set to the number of bytes that were successfully written 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_output_stream_write_async().

Since glibmm 2.44:

Parameters

  result | A AsyncResult.
  bytes_written | Location to store the number of bytes that was written to the stream.

Returns
  `true` on success, `false` if there was an error.

Exceptions

  Glib::Error |

## write_async() [1/2]

void Gio::OutputStream::write_async | ( | const void * | buffer,
|  | gsize | count,
|  | const SlotAsyncReady& | slot,
|  | const Glib::RefPtr< Cancellable >& | cancellable,
|  | int | io_priority = `Glib::PRIORITY_DEFAULT`
| ) |  |

Request an asynchronous write of count bytes from buffer into the stream.

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

During an async request no other sync and async calls are allowed, and will result in Gio::Error with PENDING being thrown.

A value of count larger than MAXSSIZE will cause a Gio::Error with INVALID_ARGUMENT to be thrown.

On success, the number of bytes written will be passed to the callback slot. It is not an error if this is not the same as the requested size, as it can happen e.g. on a partial I/O error, but generally we try to write as many bytes as requested.

Any outstanding I/O request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is Glib::PRIORITY_DEFAULT.

The asyncronous 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.

For the synchronous, blocking version of this function, see write().

Note that no copy of buffer will be made, so it must stay valid until slot is called. See write_bytes_async() for a Glib::Bytes version that will automatically hold a reference to the contents (without copying) for the duration of the call.

Parameters

  buffer | The buffer containing the data to write.
  count | The number of bytes to write
  slot | Callback slot to call when the request is satisfied.
  cancellable | Cancellable object.
  io_priority | The io priority of the request.

## write_async() [2/2]

void Gio::OutputStream::write_async | ( | const void * | buffer,
|  | gsize | count,
|  | const SlotAsyncReady& | slot,
|  | int | io_priority = `Glib::PRIORITY_DEFAULT`
| ) |  |

Request an asynchronous write of count bytes from buffer into the stream.

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

During an async request no other sync and async calls are allowed, and will result in Gio::Error with PENDING being thrown.

A value of count larger than MAXSSIZE will cause a Gio::Error with INVALID_ARGUMENT to be thrown.

On success, the number of bytes written will be passed to the callback slot. It is not an error if this is not the same as the requested size, as it can happen e.g. on a partial I/O error, but generally we try to write as many bytes as requested.

Any outstanding I/O request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is Glib::PRIORITY_DEFAULT.

The asyncronous 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.

For the synchronous, blocking version of this function, see write().

Note that no copy of buffer will be made, so it must stay valid until slot is called. See write_bytes_async() for a Glib::Bytes version that will automatically hold a reference to the contents (without copying) for the duration of the call.

Parameters

  buffer | The buffer containing the data to write.
  count | The number of bytes to write
  slot | Callback slot to call when the request is satisfied.
  io_priority | The io priority of the request.

## write_bytes() [1/2]

gssize Gio::OutputStream::write_bytes | ( | const Glib::RefPtr< const Glib::Bytes >& | bytes,
|  | const Glib::RefPtr< Cancellable >& | cancellable
| ) |  |

A wrapper function for g_output_stream_write() which takes a Bytes as input.

This can be more convenient for use by language bindings or in other cases where the refcounted nature of Bytes is helpful over a bare pointer interface.

However, note that this function may still perform partial writes, just like g_output_stream_write(). If that occurs, to continue writing, you will need to create a new Bytes containing just the remaining bytes, using Glib::bytes_new_from_bytes(). Passing the same Bytes instance multiple times potentially can result in duplicated data in the output stream.

Parameters

  bytes | The Bytes to write.
  cancellable | Optional cancellable object.

Returns
  Number of bytes written, or -1 on error.

Exceptions

  Glib::Error |

## write_bytes() [2/2]

gssize Gio::OutputStream::write_bytes | ( | const Glib::RefPtr< const Glib::Bytes >& | bytes | ) |

A write_bytes() convenience overload.

## write_bytes_async() [1/2]

void Gio::OutputStream::write_bytes_async | ( | const Glib::RefPtr< const Glib::Bytes >& | bytes,
|  | const SlotAsyncReady& | slot,
|  | const Glib::RefPtr< Cancellable >& | cancellable,
|  | int | io_priority = `Glib::PRIORITY_DEFAULT`
| ) |  |

Request an asynchronous write of the data in bytes to the stream.

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

During an async request no other sync and async calls are allowed, and will result in Gio::Error with PENDING being thrown.

A Glib:Bytes larger than MAXSSIZE will cause a Gio::Error with INVALID_ARGUMENT to be thrown.

On success, the number of bytes written will be passed to the callback slot. It is not an error if this is not the same as the requested size, as it can happen e.g. on a partial I/O error, but generally we try to write as many bytes as requested.

You are guaranteed that this method will never fail with IO_ERROR_WOULD_BLOCK - if the stream can't accept more data, the method will just wait until this changes.

Any outstanding I/O request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is Glib::PRIORITY_DEFAULT.

For the synchronous, blocking version of this function, see write_bytes().

Parameters

  bytes | The bytes to
  slot | Callback slot to call when the request is satisfied.
  cancellable | Cancellable object.
  io_priority | The io priority of the request.

Since glibmm 2.34:

## write_bytes_async() [2/2]

void Gio::OutputStream::write_bytes_async | ( | const Glib::RefPtr< const Glib::Bytes >& | bytes,
|  | const SlotAsyncReady& | slot,
|  | int | io_priority = `Glib::PRIORITY_DEFAULT`
| ) |  |

Request an asynchronous write of the data in bytes to the stream.

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

During an async request no other sync and async calls are allowed, and will result in Gio::Error with PENDING being thrown.

A Glib:Bytes larger than MAXSSIZE will cause a Gio::Error with INVALID_ARGUMENT to be thrown.

On success, the number of bytes written will be passed to the callback slot. It is not an error if this is not the same as the requested size, as it can happen e.g. on a partial I/O error, but generally we try to write as many bytes as requested.

You are guaranteed that this method will never fail with IO_ERROR_WOULD_BLOCK - if the stream can't accept more data, the method will just wait until this changes.

Any outstanding I/O request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is Glib::PRIORITY_DEFAULT.

For the synchronous, blocking version of this function, see write_bytes().

Parameters

  bytes | The bytes to
  slot | Callback slot to call when the request is satisfied.
  io_priority | The io priority of the request.

Since glibmm 2.34:

## write_bytes_finish()

gssize Gio::OutputStream::write_bytes_finish | ( | const Glib::RefPtr< AsyncResult >& | result | ) |

Finishes a stream write-from-Bytes operation.

Parameters

  result | A AsyncResult.

Returns
  A #gssize containing the number of bytes written to the stream.

Exceptions

  Glib::Error |

## write_finish()

gssize Gio::OutputStream::write_finish | ( | const Glib::RefPtr< AsyncResult >& | result | ) |

Finishes a stream write operation.

Parameters

  result | A AsyncResult.

Returns
  A #gssize containing the number of bytes written to the stream.

Exceptions

  Glib::Error |

## Friends And Related Function Documentation

## wrap()

Glib::RefPtr< Gio::OutputStream > wrap | ( | GOutputStream * | 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.