Glib::IOChannel Class Reference

IOChannel aims to provide portable I/O support for files, pipes and sockets, and to integrate them with the GLib main event loop. More...

Inheritance diagram for Glib::IOChannel:

[legend]List of all members.


Public Methods
virtual	~IOChannel ()
IOStatus	read (gunichar& unichar)
	Read a single UCS-4 character.
IOStatus	read (char* buf, gsize count, gsize& bytes_read)
	Read a character sequence into memory.
IOStatus	read (Glib::ustring& str, gsize count)
	Read a maximum of count bytes into str.
IOStatus	read_line (Glib::ustring& line)
	Read a whole line.
IOStatus	read_to_end (Glib::ustring& str)
	Reads all the remaining data from the file.
IOStatus	write (const Glib::ustring& str)
	Write a string to the I/O channel.
IOStatus	write (const char* buf, gssize count, gsize& bytes_written)
	Write a memory area of count* bytes to the I/O channel.*
IOStatus	write (gunichar unichar)
	Write a single UCS-4 character to the I/O channel.
IOStatus	seek (gint64 offset, SeekType type=SEEK_TYPE_SET)
	Seek the I/O channel to a specific position.
IOStatus	flush ()
	Flush the buffers of the I/O channel.
IOStatus	close (bool flush=true)
	Close the I/O channel.
gsize	get_buffer_size () const
	Get the IOChannel internal buffer size.
void	set_buffer_size (gsize size)
	Set the internal IOChannel buffer size.
IOFlags	get_flags () const
	Get the current flags for a IOChannel, including read-only flags such as Glib::IO_FLAG_IS_READABLE.
IOStatus	set_flags (IOFlags flags)
	Set flags on the IOChannel.
void	set_buffered (bool buffered)
	Set the buffering status of the I/O channel.
bool	get_buffered () const
	Get the buffering status of the I/O channel.
IOCondition	get_buffer_condition () const
	Returns an IOCondition depending on whether there is data to be read/space to write data in the internal buffers in the I/O channel.
bool	get_close_on_unref () const
	Returns whether the file/socket/whatever associated with the I/O channel will be closed when the channel receives its final unref and is destroyed.
void	set_close_on_unref (bool do_close)
	Setting this flag to `true` for a channel you have already closed can cause problems.
IOStatus	set_encoding (const std::string& encoding=std::string())
	Sets the encoding for the input/output of the channel.
std::string	get_encoding () const
	Get the encoding of the I/O channel.
void	set_line_term (const std::string& term=std::string())
std::string	get_line_term () const
Glib::RefPtr<IOSource>	create_watch (IOCondition condition)
	Creates an IOSource object.
virtual void	reference () const
virtual void	unreference () const
GIOChannel*	gobj ()
const GIOChannel*	gobj () const
Static Public Methods
Glib::RefPtr<IOChannel>	create_from_file (const std::string& filename, const std::string& mode)
	Open a file filename as an I/O channel using mode mode.
Glib::RefPtr<IOChannel>	create_from_fd (int fd)
	Creates an I/O channel from a file descriptor.
Glib::RefPtr<IOChannel>	create_from_win32_fd (int fd)
	Create an I/O channel for C runtime (emulated Unix-like) file descriptors.
Glib::RefPtr<IOChannel>	create_from_win32_socket (int socket)
	Create an I/O channel for a winsock socket.
Protected Methods
	IOChannel ()
	Constructor that should be used by derived classes.
virtual IOStatus	read_vfunc (char* buf, gsize count, gsize& bytes_read)
virtual IOStatus	write_vfunc (const char* buf, gsize count, gsize& bytes_written)
virtual IOStatus	seek_vfunc (gint64 offset, SeekType type)
virtual IOStatus	close_vfunc ()
virtual IOStatus	set_flags_vfunc (IOFlags flags)
virtual IOFlags	get_flags_vfunc ()
virtual Glib::RefPtr<Glib::Source>	create_watch_vfunc (IOCondition cond)
Protected Attributes
GIOChannel*	gobject_

Detailed Description

IOChannel aims to provide portable I/O support for files, pipes and sockets, and to integrate them with the GLib main event loop.

Note that IOChannels implement an automatic implicit character set conversion to the data stream, and usually will not pass by default binary data unchanged. To set the encoding of the channel, use e.g. set_encoding("ISO-8859-15"). To set the channel to no encoding, use set_encoding() without any arguments.

You can create an IOChannel with one of the static create methods, or implement one yourself, in which case you have to 1) override all _vfunc() members. 2) set the GIOChannel flags in your constructor.

Note:: This feature of being able to implement a custom Glib::IOChannel is deprecated in glibmm 2.2. The vfunc interface has not yet stabilized enough to allow that -- the C++ wrapper went in by pure accident. Besides, it isn't terribly useful either. Thus please refrain from overriding any IOChannel vfuncs.

Constructor & Destructor Documentation

virtual Glib::IOChannel::~IOChannel ( ) [virtual]

Glib::IOChannel::IOChannel ( ) [protected]

Constructor that should be used by derived classes.
Use this constructor if you want to inherit from IOChannel. It will set up a GIOChannel that will call the vfuncs of your class even if it is being used from C code, and it will keep a reference to the C++ code while the GIOChannel exists.

Member Function Documentation

IOStatus Glib::IOChannel::close ( bool flush = true )

Close the I/O channel.
Any pending data to be written will be flushed if flush is true. The channel will not be freed until the last reference is dropped. Accessing the channel after closing it is considered an error.
Parameters:

flush Whether to flush() pending data before closing the channel.

Returns:
The status of the operation.

Exceptions:

Glib::IOChannelError

virtual IOStatus Glib::IOChannel::close_vfunc ( ) [protected, virtual]

Reimplemented in Glib::StreamIOChannel.

Glib::RefPtr<IOChannel> Glib::IOChannel::create_from_fd ( int fd ) [static]

Creates an I/O channel from a file descriptor.
On Unix, IOChannels created with this function work for any file descriptor or socket.
On Win32, this can be used either for files opened with the MSVCRT (the Microsoft run-time C library) _open() or _pipe(), including file descriptors 0, 1 and 2 (corresponding to stdin, stdout and stderr), or for Winsock SOCKETs. If the parameter is a legal file descriptor, it is assumed to be such, otherwise it should be a SOCKET. This relies on SOCKETs and file descriptors not overlapping. If you want to be certain, call either create_from_win32_fd() or create_from_win32_socket() instead as appropriate.
The term file descriptor as used in the context of Win32 refers to the emulated Unix-like file descriptors MSVCRT provides. The native corresponding concept is file HANDLE. There isn't as of yet a way to get IOChannels for Win32 file HANDLEs.

Glib::RefPtr<IOChannel> Glib::IOChannel::create_from_file ( const std::string& filename,

const std::string& mode

) [static]

Open a file filename as an I/O channel using mode mode.
This channel will be closed when the last reference to it is dropped, so there is no need to call close() (though doing so will not cause problems, as long as no attempt is made to access the channel after it is closed).
Parameters:

filename The name of the file to open.

mode One of "r", "w", "a", "r+", "w+", "a+". These have the same meaning as in fopen().

Returns:
An IOChannel for the opened file.

Exceptions:

Glib::FileError

Glib::RefPtr<IOChannel> Glib::IOChannel::create_from_win32_fd ( int fd ) [static]

Create an I/O channel for C runtime (emulated Unix-like) file descriptors.
After calling add_watch() on a I/O channel returned by this function, you shouldn't call read() on the file descriptor. This is because adding polling for a file descriptor is implemented on Win32 by starting a thread that sits blocked in a read() from the file descriptor most of the time. All reads from the file descriptor should be done by this internal GLib thread. Your code should call only IOChannel::read().

Glib::RefPtr<IOChannel> Glib::IOChannel::create_from_win32_socket ( int socket ) [static]

Create an I/O channel for a winsock socket.
The parameter should be a SOCKET. Contrary to I/O channels for file descriptors (on Win32), you can use normal recv() or recvfrom() on sockets even if GLib is polling them.

Glib::RefPtr<IOSource> Glib::IOChannel::create_watch ( IOCondition condition )

Creates an IOSource object.
Create a slot from a function to be called when condition is met for the channel with SigC::slot() and pass it into the connect() function of the returned IOSource object. Polling of the channel will start when you attach a MainContext object to the returned IOSource object using its attach() function.
Glib::signal_io().connect() is a simpler interface to the same functionality, for the case where you want to add the source to the default main context.
Parameters:

condition The condition to watch for.

Returns:
An IOSource object that can be polled from a MainContext's event loop.

virtual Glib::RefPtr<Glib::Source> Glib::IOChannel::create_watch_vfunc ( IOCondition cond ) [protected, virtual]

Reimplemented in Glib::StreamIOChannel.

IOStatus Glib::IOChannel::flush ( )

Flush the buffers of the I/O channel.

Returns:
The status of the operation.

Exceptions:

Glib::IOChannelError

Glib::ConvertError

IOCondition Glib::IOChannel::get_buffer_condition ( ) const

Returns an IOCondition depending on whether there is data to be read/space to write data in the internal buffers in the I/O channel.
Only the flags Glib::IO_IN and Glib::IO_OUT may be set.
Returns:
Bitwise combination of Glib::IOCondition flags.

gsize Glib::IOChannel::get_buffer_size ( ) const

Get the IOChannel internal buffer size.

Returns:
The buffer size.

bool Glib::IOChannel::get_buffered ( ) const

Get the buffering status of the I/O channel.

Returns:
The buffering status of the channel.

bool Glib::IOChannel::get_close_on_unref ( ) const

Returns whether the file/socket/whatever associated with the I/O channel will be closed when the channel receives its final unref and is destroyed.
The default value of this is true for channels created by create_from_file(), and false for all other channels.
Returns:
Whether the channel will be closed on the final unref of the IOChannel object.

std::string Glib::IOChannel::get_encoding ( ) const

Get the encoding of the I/O channel.

Returns:
The current encoding of the channel.

IOFlags Glib::IOChannel::get_flags ( ) const

Get the current flags for a IOChannel, including read-only flags such as Glib::IO_FLAG_IS_READABLE.
The values of the flags Glib::IO_FLAG_IS_READABLE and Glib::IO_FLAG_IS_WRITEABLE are cached for internal use by the channel when it is created. If they should change at some later point (e.g. partial shutdown of a socket with the UNIX shutdown() function), the user should immediately call get_flags() to update the internal values of these flags.
Returns:
Bitwise combination of the flags set on the channel.

virtual IOFlags Glib::IOChannel::get_flags_vfunc ( ) [protected, virtual]

Reimplemented in Glib::StreamIOChannel.

std::string Glib::IOChannel::get_line_term ( ) const

const GIOChannel* Glib::IOChannel::gobj ( ) const [inline]

GIOChannel* Glib::IOChannel::gobj ( ) [inline]

IOStatus Glib::IOChannel::read ( Glib::ustring& str,

gsize count

)

Read a maximum of count bytes into str.

Parameters:

count The maximum number of bytes to read.

Return values:

str The characters that have been read.

Returns:
The status of the operation.

Exceptions:

Glib::IOChannelError

Glib::ConvertError

IOStatus Glib::IOChannel::read ( char* buf,

gsize count,

gsize& bytes_read

)

Read a character sequence into memory.

Parameters:

buf A buffer to read data into.

count The size of the buffer in bytes. Note that the buffer may not be complelely filled even if there is data in the buffer if the remaining data is not a complete character.

Return values:

bytes_read The number of bytes read. This may be zero even on success if count < 6 and the channel's encoding is not "". This indicates that the next UTF-8 character is too wide for the buffer.

Returns:
The status of the operation.

Exceptions:

Glib::IOChannelError

Glib::ConvertError

IOStatus Glib::IOChannel::read ( gunichar& unichar )

Read a single UCS-4 character.

Return values:

unichar The Unicode character.

Returns:
The status of the operation.

Exceptions:

Glib::IOChannelError

Glib::ConvertError

IOStatus Glib::IOChannel::read_line ( Glib::ustring& line )

Read a whole line.
Reads until the line separator is found, which is included in the result string.
Return values:

line The line that was read.

Returns:
The status of the operation.

Exceptions:

Glib::IOChannelError

Glib::ConvertError

IOStatus Glib::IOChannel::read_to_end ( Glib::ustring& str )

Reads all the remaining data from the file.

Return values:

str The resulting string.

Returns:
Glib::IO_STATUS_NORMAL on success. This function never returns Glib::IO_STATUS_EOF.

Exceptions:

Glib::IOChannelError

Glib::ConvertError

virtual IOStatus Glib::IOChannel::read_vfunc ( char* buf,

gsize count,

gsize& bytes_read

) [protected, virtual]

Reimplemented in Glib::StreamIOChannel.

virtual void Glib::IOChannel::reference ( ) const [virtual]

IOStatus Glib::IOChannel::seek ( gint64 offset,

SeekType type = SEEK_TYPE_SET

)

Seek the I/O channel to a specific position.

Parameters:

offset The offset in bytes from the position specified by type.

type A SeekType. The type Glib::SEEK_TYPE_CUR is only allowed in those cases where a call to set_encoding() is allowed. See the documentation for set_encoding() for details.

Returns:
The status of the operation.

Exceptions:

Glib::IOChannelError

Glib::ConvertError

virtual IOStatus Glib::IOChannel::seek_vfunc ( gint64 offset,

SeekType type

) [protected, virtual]

Reimplemented in Glib::StreamIOChannel.

void Glib::IOChannel::set_buffer_size ( gsize size )

Set the internal IOChannel buffer size.

Parameters:

size The buffer size the IOChannel should use.

void Glib::IOChannel::set_buffered ( bool buffered )

Set the buffering status of the I/O channel.
The buffering state can only be set if the channel's encoding is "". For any other encoding, the channel must be buffered.
A buffered channel can only be set unbuffered if the channel's internal buffers have been flushed. Newly created channels or channels which have returned Glib::IO_STATUS_EOF not require such a flush. For write-only channels, a call to flush() is sufficient. For all other channels, the buffers may be flushed by a call to seek(). This includes the possibility of seeking with seek type Glib::SEEK_TYPE_CUR and an offset of zero. Note that this means that socket-based channels cannot be set unbuffered once they have had data read from them.
The default state of the channel is buffered.

Parameters:

buffered Whether to set the channel buffered or unbuffered.

void Glib::IOChannel::set_close_on_unref ( bool do_close )

Setting this flag to true for a channel you have already closed can cause problems.

Parameters:

do_close Whether to close the channel on the final unref of the IOChannel object. The default value of this is true for channels created by create_from_file(), and false for all other channels.

IOStatus Glib::IOChannel::set_encoding ( const std::string& encoding = std::string() )

Sets the encoding for the input/output of the channel.
The internal encoding is always UTF-8. The default encoding for the external file is UTF-8. The encoding "" is safe to use with binary data.
The encoding can only be set if one of the following conditions is true:

The channel was just created, and has not been written to or read from yet.
The channel is write-only.
The channel is a file, and the file pointer was just repositioned by a call to seek_position(). (This flushes all the internal buffers.)
The current encoding is "" or UTF-8.
One of the read methods has just returned Glib::IO_STATUS_EOF (or, in the case of read_to_end(), Glib::IO_STATUS_NORMAL).
The read() method has returned Glib::IO_STATUS_AGAIN or thrown a Glib::Error exception. This may be useful in the case of ConvertError::ILLEGAL_SEQUENCE. Returning one of these statuses from read_line() or read_to_end() does not guarantee that the encoding can be changed.

Channels which do not meet one of the above conditions cannot call seek_position() with a seek type of Glib::SEEK_TYPE_CUR and, if they are "seekable", cannot call write() after calling one of the API "read" methods.

Parameters:

encoding The encoding name, or "" for binary.

Returns:
Glib::IO_STATUS_NORMAL if the encoding was successfully set.

Exceptions:

Glib::IOChannelError

IOStatus Glib::IOChannel::set_flags ( IOFlags flags )

Set flags on the IOChannel.

Parameters:

flags Bitwise combination of the flags to set.

Returns:
The operation result code.

Exceptions:

Glib::IOChannelError

virtual IOStatus Glib::IOChannel::set_flags_vfunc ( IOFlags flags ) [protected, virtual]

Reimplemented in Glib::StreamIOChannel.

void Glib::IOChannel::set_line_term ( const std::string& term = std::string() )

virtual void Glib::IOChannel::unreference ( ) const [virtual]

IOStatus Glib::IOChannel::write ( gunichar unichar )

Write a single UCS-4 character to the I/O channel.

Parameters:

unichar The character to write.

Returns:
The status of the operation.

Exceptions:

Glib::IOChannelError

Glib::ConvertError

IOStatus Glib::IOChannel::write ( const char* buf,

gssize count,

gsize& bytes_written

)

Write a memory area of count bytes to the I/O channel.

Parameters:

buf The start of the memory area.

count The number of bytes to write.

Return values:

bytes_written The number of bytes written to the channel.

Returns:
The status of the operation.

Exceptions:

Glib::IOChannelError

Glib::ConvertError

IOStatus Glib::IOChannel::write ( const Glib::ustring& str )

Write a string to the I/O channel.
Note that this method does not return the number of characters written. If the channel is blocking and the returned value is Glib::IO_STATUS_NORMAL, the whole string was written.
Parameters:

str the string to write.

Returns:
The status of the operation.

Exceptions:

Glib::IOChannelError

Glib::ConvertError

virtual IOStatus Glib::IOChannel::write_vfunc ( const char* buf,

gsize count,

gsize& bytes_written

) [protected, virtual]

Reimplemented in Glib::StreamIOChannel.

Member Data Documentation

GIOChannel* Glib::IOChannel::gobject_ [protected]

The documentation for this class was generated from the following file:

iochannel.h

Glib::IOChannel Class Reference

Public Methods

Static Public Methods

Protected Methods

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation