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GLib Reference Manual | ![]() |
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#include <glib.h> GIOChannel; GIOChannel* g_io_channel_unix_new (int fd); gint g_io_channel_unix_get_fd (GIOChannel *channel); GIOChannel* g_io_channel_win32_new_fd (gint fd); GIOChannel * g_io_channel_win32_new_socket (gint socket); GIOChannel * g_io_channel_win32_new_messages (gsize hwnd); void g_io_channel_init (GIOChannel *channel); GIOChannel* g_io_channel_new_file (const gchar *filename, const gchar *mode, GError **error); GIOStatus g_io_channel_read_chars (GIOChannel *channel, gchar *buf, gsize count, gsize *bytes_read, GError **error); GIOStatus g_io_channel_read_unichar (GIOChannel *channel, gunichar *thechar, GError **error); GIOStatus g_io_channel_read_line (GIOChannel *channel, gchar **str_return, gsize *length, gsize *terminator_pos, GError **error); GIOStatus g_io_channel_read_line_string (GIOChannel *channel, GString *buffer, gsize *terminator_pos, GError **error); GIOStatus g_io_channel_read_to_end (GIOChannel *channel, gchar **str_return, gsize *length, GError **error); GIOStatus g_io_channel_write_chars (GIOChannel *channel, const gchar *buf, gssize count, gsize *bytes_written, GError **error); GIOStatus g_io_channel_write_unichar (GIOChannel *channel, gunichar thechar, GError **error); GIOStatus g_io_channel_flush (GIOChannel *channel, GError **error); GIOStatus g_io_channel_seek_position (GIOChannel *channel, gint64 offset, GSeekType type, GError **error); enum GSeekType; GIOStatus g_io_channel_shutdown (GIOChannel *channel, gboolean flush, GError **err); enum GIOStatus; enum GIOChannelError; #define G_IO_CHANNEL_ERROR GIOChannelError g_io_channel_error_from_errno (gint en); GIOChannel * g_io_channel_ref (GIOChannel *channel); void g_io_channel_unref (GIOChannel *channel); GSource * g_io_create_watch (GIOChannel *channel, GIOCondition condition); guint g_io_add_watch (GIOChannel *channel, GIOCondition condition, GIOFunc func, gpointer user_data); guint g_io_add_watch_full (GIOChannel *channel, gint priority, GIOCondition condition, GIOFunc func, gpointer user_data, GDestroyNotify notify); enum GIOCondition; gboolean (*GIOFunc) (GIOChannel *source, GIOCondition condition, gpointer data); GIOFuncs; gsize g_io_channel_get_buffer_size (GIOChannel *channel); void g_io_channel_set_buffer_size (GIOChannel *channel, gsize size); GIOCondition g_io_channel_get_buffer_condition (GIOChannel *channel); GIOFlags g_io_channel_get_flags (GIOChannel *channel); GIOStatus g_io_channel_set_flags (GIOChannel *channel, GIOFlags flags, GError **error); enum GIOFlags; const gchar* g_io_channel_get_line_term (GIOChannel *channel, gint *length); void g_io_channel_set_line_term (GIOChannel *channel, const gchar *line_term, gint length); gboolean g_io_channel_get_buffered (GIOChannel *channel); void g_io_channel_set_buffered (GIOChannel *channel, gboolean buffered); const gchar* g_io_channel_get_encoding (GIOChannel *channel); GIOStatus g_io_channel_set_encoding (GIOChannel *channel, const gchar *encoding, GError **error); gboolean g_io_channel_get_close_on_unref (GIOChannel *channel); void g_io_channel_set_close_on_unref (GIOChannel *channel, gboolean do_close); GIOError g_io_channel_read (GIOChannel *channel, gchar *buf, gsize count, gsize *bytes_read); enum GIOError; GIOError g_io_channel_write (GIOChannel *channel, const gchar *buf, gsize count, gsize *bytes_written); GIOError g_io_channel_seek (GIOChannel *channel, gint64 offset, GSeekType type); void g_io_channel_close (GIOChannel *channel);
The GIOChannel data type aims to provide a portable method for using file descriptors, pipes, and sockets, and integrating them into the main event loop. Currently full support is available on UNIX platforms, support for Windows is only partially complete.
To create a new GIOChannel on UNIX systems use g_io_channel_unix_new()
.
This works for plain file descriptors, pipes and sockets.
Alternatively, a channel can be created for a file in a system independent
manner using g_io_channel_new_file()
.
Once a GIOChannel has been created, it can be used in a generic manner
with the functions g_io_channel_read_chars()
, g_io_channel_write_chars()
,
g_io_channel_seek_position()
, and g_io_channel_shutdown()
.
To add a GIOChannel to the
main event loop
use g_io_add_watch()
or g_io_add_watch_full()
. Here you specify which events
you are interested in on the GIOChannel, and provide a function to be
called whenever these events occur.
GIOChannel instances are created with an initial reference count of 1.
g_io_channel_ref()
and g_io_channel_unref()
can be used to increment or
decrement the reference count respectively. When the reference count falls
to 0, the GIOChannel is freed. (Though it isn't closed automatically,
unless it was created using g_io_channel_new_from_file()
.)
Using g_io_add_watch()
or g_io_add_watch_full()
increments a channel's
reference count.
The new functions g_io_channel_read_chars()
, g_io_channel_read_line()
,
g_io_channel_read_line_string()
, g_io_channel_read_to_end()
,
g_io_channel_write_chars()
, g_io_channel_seek_position()
,
and g_io_channel_flush()
should not be mixed with the
deprecated functions g_io_channel_read()
, g_io_channel_write()
,
and g_io_channel_seek()
on the same channel.
typedef struct { } GIOChannel;
A data structure representing an IO Channel. The fields should be considered private and should only be accessed with the following functions.
GIOChannel* g_io_channel_unix_new (int fd);
Creates a new GIOChannel given a file descriptor. On UNIX systems this works for plain files, pipes, and sockets.
The returned GIOChannel has a reference count of 1.
The default encoding for GIOChannel is UTF-8. If your application
is reading output from a command using via pipe, you may need to
set the encoding to the encoding of the current locale (see
g_get_charset()
) with the g_io_channel_set_encoding()
function.
If you want to read raw binary data without interpretation, then
call the g_io_channel_set_encoding()
function with NULL
for the
encoding argument.
This function is available in GLib on Windows, too, but you should avoid using it on Windows. The domain of file descriptors and sockets overlap. There is no way for GLib to know which one you mean in case the argument you pass to this function happens to be both a valid file descriptor and socket. If that happens a warning is issued, and GLib assumes that it is the file descriptor you mean.
|
a file descriptor. |
Returns : |
a new GIOChannel. |
gint g_io_channel_unix_get_fd (GIOChannel *channel);
Returns the file descriptor of the GIOChannel.
On Windows this function returns the file descriptor or socket of the GIOChannel.
|
a GIOChannel, created with g_io_channel_unix_new() .
|
Returns : |
the file descriptor of the GIOChannel. |
GIOChannel* g_io_channel_win32_new_fd (gint fd);
Creates a new GIOChannel given a file descriptor on Windows. This works for file descriptors from the C runtime.
This function works for file descriptors as returned by the open()
,
creat()
, pipe()
and fileno()
calls in the Microsoft C runtime. In
order to meaningfully use this function your code should use the same
C runtime as GLib uses, which is msvcrt.dll. Note that in current
Microsoft compilers it is near impossible to convince it to build code
that would use msvcrt.dll. The last Microsoft compiler version that
supported using msvcrt.dll as the C runtime was version 6. The GNU
compiler and toolchain for Windows, also known as Mingw, fully
supports msvcrt.dll.
If you have created a GIOChannel for a file descriptor and started
watching (polling) it, you shouldn't call read()
on the file
descriptor. This is because adding polling for a file descriptor is
implemented in GLib on Windows 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 g_io_channel_read()
.
This function is available only in GLib on Windows.
|
a C library file descriptor. |
Returns : |
a new GIOChannel. |
GIOChannel * g_io_channel_win32_new_socket (gint socket);
Creates a new GIOChannel given a socket on Windows.
This function works for sockets created by Winsock. It's available only in GLib on Windows.
Polling a GSource created to watch a channel for a socket puts the socket in non-blocking mode. This is a side-effect of the implementation and unavoidable.
|
a Winsock socket |
Returns : |
a new GIOChannel |
GIOChannel * g_io_channel_win32_new_messages (gsize hwnd);
Creates a new GIOChannel given a window handle on Windows.
This function creates a GIOChannel that can be used to poll for Windows messages for the window in question.
|
a window handle. |
Returns : |
a new GIOChannel. |
void g_io_channel_init (GIOChannel *channel);
Initializes a GIOChannel struct.
This is called by each of the above functions when creating a GIOChannel, and so is not often needed by the application programmer (unless you are creating a new type of GIOChannel).
|
a GIOChannel |
GIOChannel* g_io_channel_new_file (const gchar *filename, const gchar *mode, GError **error);
Open a file filename
as a GIOChannel using mode mode
. This
channel will be closed when the last reference to it is dropped,
so there is no need to call g_io_channel_close()
(though doing
so will not cause problems, as long as no attempt is made to
access the channel after it is closed).
|
A string containing the name of a file |
|
One of "r", "w", "a", "r+", "w+", "a+". These have
the same meaning as in fopen()
|
|
A location to return an error of type G_FILE_ERROR
|
Returns : |
A GIOChannel on success, NULL on failure.
|
GIOStatus g_io_channel_read_chars (GIOChannel *channel, gchar *buf, gsize count, gsize *bytes_read, GError **error);
Replacement for g_io_channel_read()
with the new API.
|
a GIOChannel |
|
a buffer to read data into |
|
the size of the buffer. 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. |
|
The number of bytes read. This may be zero even on
success if count < 6 and the channel's encoding is non-NULL .
This indicates that the next UTF-8 character is too wide for
the buffer.
|
|
a location to return an error of type GConvertError or GIOChannelError. |
Returns : |
the status of the operation. |
GIOStatus g_io_channel_read_unichar (GIOChannel *channel, gunichar *thechar, GError **error);
Reads a Unicode character from channel
.
This function cannot be called on a channel with NULL
encoding.
|
a GIOChannel |
|
a location to return a character |
|
a location to return an error of type GConvertError or GIOChannelError |
Returns : |
a GIOStatus |
GIOStatus g_io_channel_read_line (GIOChannel *channel, gchar **str_return, gsize *length, gsize *terminator_pos, GError **error);
Reads a line, including the terminating character(s),
from a GIOChannel into a newly-allocated string.
str_return
will contain allocated memory if the return
is G_IO_STATUS_NORMAL
.
|
a GIOChannel |
|
The line read from the GIOChannel, including the
line terminator. This data should be freed with g_free()
when no longer needed. This is a nul-terminated string.
If a length of zero is returned, this will be NULL instead.
|
|
location to store length of the read data, or NULL
|
|
location to store position of line terminator, or NULL
|
|
A location to return an error of type GConvertError or GIOChannelError |
Returns : |
the status of the operation. |
GIOStatus g_io_channel_read_line_string (GIOChannel *channel, GString *buffer, gsize *terminator_pos, GError **error);
Reads a line from a GIOChannel, using a GString as a buffer.
|
a GIOChannel |
|
a GString into which the line will be written.
If buffer already contains data, the old data will
be overwritten.
|
|
location to store position of line terminator, or NULL
|
|
a location to store an error of type GConvertError or GIOChannelError |
Returns : |
the status of the operation. |
GIOStatus g_io_channel_read_to_end (GIOChannel *channel, gchar **str_return, gsize *length, GError **error);
Reads all the remaining data from the file.
|
a GIOChannel |
|
Location to store a pointer to a string holding
the remaining data in the GIOChannel. This data should
be freed with g_free() when no longer needed. This
data is terminated by an extra nul character, but there
may be other nuls in the intervening data.
|
|
location to store length of the data |
|
location to return an error of type GConvertError or GIOChannelError |
Returns : |
G_IO_STATUS_NORMAL on success.
This function never returns G_IO_STATUS_EOF .
|
GIOStatus g_io_channel_write_chars (GIOChannel *channel, const gchar *buf, gssize count, gsize *bytes_written, GError **error);
Replacement for g_io_channel_write()
with the new API.
On seekable channels with encodings other than NULL
or UTF-8, generic
mixing of reading and writing is not allowed. A call to g_io_channel_write_chars()
may only be made on a channel from which data has been read in the
cases described in the documentation for g_io_channel_set_encoding()
.
|
a GIOChannel |
|
a buffer to write data from |
|
the size of the buffer. If -1, the buffer is taken to be a nul-terminated string. |
|
The number of bytes written. This can be nonzero
even if the return value is not G_IO_STATUS_NORMAL .
If the return value is G_IO_STATUS_NORMAL and the
channel is blocking, this will always be equal
to count if count >= 0.
|
|
a location to return an error of type GConvertError or GIOChannelError |
Returns : |
the status of the operation. |
GIOStatus g_io_channel_write_unichar (GIOChannel *channel, gunichar thechar, GError **error);
Writes a Unicode character to channel
.
This function cannot be called on a channel with NULL
encoding.
|
a GIOChannel |
|
a character |
|
location to return an error of type GConvertError or GIOChannelError |
Returns : |
a GIOStatus |
GIOStatus g_io_channel_flush (GIOChannel *channel, GError **error);
Flushes the write buffer for the GIOChannel.
|
a GIOChannel |
|
location to store an error of type GIOChannelError |
Returns : |
the status of the operation: One of G_IO_STATUS_NORMAL, G_IO_STATUS_AGAIN, or G_IO_STATUS_ERROR. |
GIOStatus g_io_channel_seek_position (GIOChannel *channel, gint64 offset, GSeekType type, GError **error);
Replacement for g_io_channel_seek()
with the new API.
|
a GIOChannel |
|
The offset in bytes from the position specified by type
|
|
a GSeekType. The type G_SEEK_CUR is only allowed in those
cases where a call to g_io_channel_set_encoding()
is allowed. See the documentation for
g_io_channel_set_encoding() for details.
|
|
A location to return an error of type GIOChannelError |
Returns : |
the status of the operation. |
typedef enum { G_SEEK_CUR, G_SEEK_SET, G_SEEK_END } GSeekType;
An enumeration specifying the base position for a g_io_channel_seek_position()
operation.
GIOStatus g_io_channel_shutdown (GIOChannel *channel, gboolean flush, GError **err);
Close an IO 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 using g_io_channel_unref()
.
|
a GIOChannel |
|
if TRUE , flush pending
|
|
location to store a GIOChannelError |
Returns : |
the status of the operation. |
typedef enum { G_IO_STATUS_ERROR, G_IO_STATUS_NORMAL, G_IO_STATUS_EOF, G_IO_STATUS_AGAIN } GIOStatus;
Stati returned by most of the GIOFuncs functions.
typedef enum { /* Derived from errno */ G_IO_CHANNEL_ERROR_FBIG, G_IO_CHANNEL_ERROR_INVAL, G_IO_CHANNEL_ERROR_IO, G_IO_CHANNEL_ERROR_ISDIR, G_IO_CHANNEL_ERROR_NOSPC, G_IO_CHANNEL_ERROR_NXIO, G_IO_CHANNEL_ERROR_OVERFLOW, G_IO_CHANNEL_ERROR_PIPE, /* Other */ G_IO_CHANNEL_ERROR_FAILED } GIOChannelError;
Error codes returned by GIOChannel operations.
File too large. | |
Invalid argument. | |
IO error. | |
File is a directory. | |
No space left on device. | |
No such device or address. | |
Value too large for defined datatype. | |
Broken pipe. | |
Some other error. |
#define G_IO_CHANNEL_ERROR g_io_channel_error_quark()
Error domain for GIOChannel operations. Errors in this domain will be from the GIOChannelError enumeration. See GError for information on error domains.
GIOChannelError g_io_channel_error_from_errno (gint en);
Converts an errno
error number to a GIOChannelError.
|
an errno error number, e.g. EINVAL
|
Returns : |
a GIOChannelError error number, e.g.
G_IO_CHANNEL_ERROR_INVAL .
|
GIOChannel * g_io_channel_ref (GIOChannel *channel);
Increments the reference count of a GIOChannel.
|
a GIOChannel |
Returns : |
the channel that was passed in (since 2.6)
|
void g_io_channel_unref (GIOChannel *channel);
Decrements the reference count of a GIOChannel.
|
a GIOChannel |
GSource * g_io_create_watch (GIOChannel *channel, GIOCondition condition);
Creates a GSource that's dispatched when condition
is met for the
given channel
. For example, if condition is G_IO_IN, the source will
be dispatched when there's data available for reading.
g_io_add_watch()
is a simpler interface to this same functionality, for
the case where you want to add the source to the default main loop context
at the default priority.
On Windows, polling a GSource created to watch a channel for a socket puts the socket in non-blocking mode. This is a side-effect of the implementation and unavoidable.
|
a GIOChannel to watch |
|
conditions to watch for |
Returns : |
a new GSource |
guint g_io_add_watch (GIOChannel *channel, GIOCondition condition, GIOFunc func, gpointer user_data);
Adds the GIOChannel into the default main loop context with the default priority.
|
a GIOChannel |
|
the condition to watch for |
|
the function to call when the condition is satisfied |
|
user data to pass to func
|
Returns : |
the event source id |
guint g_io_add_watch_full (GIOChannel *channel, gint priority, GIOCondition condition, GIOFunc func, gpointer user_data, GDestroyNotify notify);
Adds the GIOChannel into the default main loop context with the given priority.
This internally creates a main loop source using g_io_create_watch()
and attaches it to the main loop context with g_source_attach()
.
You can do these steps manuallt if you need greater control.
|
a GIOChannel |
|
the priority of the GIOChannel source |
|
the condition to watch for |
|
the function to call when the condition is satisfied |
|
user data to pass to func
|
|
the function to call when the source is removed |
Returns : |
the event source id |
typedef enum { G_IO_IN GLIB_SYSDEF_POLLIN, G_IO_OUT GLIB_SYSDEF_POLLOUT, G_IO_PRI GLIB_SYSDEF_POLLPRI, G_IO_ERR GLIB_SYSDEF_POLLERR, G_IO_HUP GLIB_SYSDEF_POLLHUP, G_IO_NVAL GLIB_SYSDEF_POLLNVAL } GIOCondition;
A bitwise combination representing a condition to watch for on an event source.
gboolean (*GIOFunc) (GIOChannel *source, GIOCondition condition, gpointer data);
Specifies the type of function passed to g_io_add_watch()
or
g_io_add_watch_full()
, which is called when the requested
condition on a GIOChannel is satisfied.
|
the GIOChannel event source |
|
the condition which has been satisfied |
|
user data set in g_io_add_watch() or g_io_add_watch_full()
|
Returns : |
the function should return FALSE if the event source
should be removed
|
typedef struct { GIOStatus (*io_read) (GIOChannel *channel, gchar *buf, gsize count, gsize *bytes_read, GError **err); GIOStatus (*io_write) (GIOChannel *channel, const gchar *buf, gsize count, gsize *bytes_written, GError **err); GIOStatus (*io_seek) (GIOChannel *channel, gint64 offset, GSeekType type, GError **err); GIOStatus (*io_close) (GIOChannel *channel, GError **err); GSource* (*io_create_watch) (GIOChannel *channel, GIOCondition condition); void (*io_free) (GIOChannel *channel); GIOStatus (*io_set_flags) (GIOChannel *channel, GIOFlags flags, GError **err); GIOFlags (*io_get_flags) (GIOChannel *channel); } GIOFuncs;
A table of functions used to handle different types of GIOChannel in a generic way.
gsize g_io_channel_get_buffer_size (GIOChannel *channel);
Gets the buffer size.
|
a GIOChannel |
Returns : |
the size of the buffer. |
void g_io_channel_set_buffer_size (GIOChannel *channel, gsize size);
Sets the buffer size.
|
a GIOChannel |
|
the size of the buffer, or 0 to let GLib pick a good size |
GIOCondition g_io_channel_get_buffer_condition (GIOChannel *channel);
This function returns a GIOCondition depending on whether there
is data to be read/space to write data in the internal buffers in
the GIOChannel. Only the flags G_IO_IN
and G_IO_OUT
may be set.
|
A GIOChannel |
Returns : |
A GIOCondition |
GIOFlags g_io_channel_get_flags (GIOChannel *channel);
Gets the current flags for a GIOChannel, including read-only
flags such as G_IO_FLAG_IS_READABLE
.
The values of the flags G_IO_FLAG_IS_READABLE
and G_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 g_io_channel_get_flags()
to update
the internal values of these flags.
|
a GIOChannel |
Returns : |
the flags which are set on the channel |
GIOStatus g_io_channel_set_flags (GIOChannel *channel, GIOFlags flags, GError **error);
Sets the (writeable) flags in channel
to (flags
& G_IO_CHANNEL_SET_MASK
).
|
a GIOChannel |
|
the flags to set on the IO channel |
|
A location to return an error of type GIOChannelError |
Returns : |
the status of the operation. |
typedef enum { G_IO_FLAG_APPEND = 1 << 0, G_IO_FLAG_NONBLOCK = 1 << 1, G_IO_FLAG_IS_READABLE = 1 << 2, /* Read only flag */ G_IO_FLAG_IS_WRITEABLE = 1 << 3, /* Read only flag */ G_IO_FLAG_IS_SEEKABLE = 1 << 4, /* Read only flag */ G_IO_FLAG_MASK = (1 << 5) - 1, G_IO_FLAG_GET_MASK = G_IO_FLAG_MASK, G_IO_FLAG_SET_MASK = G_IO_FLAG_APPEND | G_IO_FLAG_NONBLOCK } GIOFlags;
Specifies properties of a GIOChannel. Some of the flags can only
be read with g_io_channel_get_flags()
, but not changed with
g_io_channel_set_flags()
.
turns on append mode, corresponds to O_APPEND
(see the documentation of the UNIX open() syscall).
|
|
turns on nonblocking mode, corresponds to
O_NONBLOCK /O_NDELAY (see the documentation of the UNIX open()
syscall).
|
|
indicates that the io channel is readable. This flag can not be changed. | |
indicates that the io channel is writable. This flag can not be changed. | |
indicates that the io channel is seekable,
i.e. that g_io_channel_seek_position() can be used on it.
This flag can not be changed.
|
|
const gchar* g_io_channel_get_line_term (GIOChannel *channel, gint *length);
This returns the string that GIOChannel uses to determine
where in the file a line break occurs. A value of NULL
indicates autodetection.
|
a GIOChannel |
|
a location to return the length of the line terminator |
Returns : |
The line termination string. This value is owned by GLib and must not be freed. |
void g_io_channel_set_line_term (GIOChannel *channel, const gchar *line_term, gint length);
This sets the string that GIOChannel uses to determine where in the file a line break occurs.
|
a GIOChannel |
|
The line termination string. Use NULL for autodetect.
Autodetection breaks on "\n", "\r\n", "\r", "\0", and
the Unicode paragraph separator. Autodetection should
not be used for anything other than file-based channels.
|
|
The length of the termination string. If -1 is passed, the string is assumed to be nul-terminated. This option allows termination strings with embedded nuls. |
gboolean g_io_channel_get_buffered (GIOChannel *channel);
Returns whether channel
is buffered.
|
a GIOChannel |
Returns : |
TRUE if the channel is buffered.
|
void g_io_channel_set_buffered (GIOChannel *channel, gboolean buffered);
The buffering state can only be set if the channel's encoding
is NULL
. 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 G_IO_STATUS_EOF
not require such a flush. For write-only channels, a call to
g_io_channel_flush()
is sufficient. For all other channels,
the buffers may be flushed by a call to g_io_channel_seek_position()
.
This includes the possibility of seeking with seek type G_SEEK_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.
On unbuffered channels, it is safe to mix read and write calls from the new and old APIs, if this is necessary for maintaining old code.
The default state of the channel is buffered.
|
a GIOChannel |
|
whether to set the channel buffered or unbuffered |
const gchar* g_io_channel_get_encoding (GIOChannel *channel);
Gets the encoding for the input/output of the channel.
The internal encoding is always UTF-8. The encoding NULL
makes the channel safe for binary data.
|
a GIOChannel |
Returns : |
A string containing the encoding, this string is owned by GLib and must not be freed. |
GIOStatus g_io_channel_set_encoding (GIOChannel *channel, const gchar *encoding, GError **error);
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 NULL
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 g_io_channel_seek_position()
.
(This flushes all the internal buffers.)
The current encoding is NULL
or UTF-8.
One of the (new API) read functions has just returned G_IO_STATUS_EOF
(or, in the case of g_io_channel_read_to_end()
, G_IO_STATUS_NORMAL
).
One of the functions g_io_channel_read_chars()
or
g_io_channel_read_unichar()
has returned G_IO_STATUS_AGAIN
or
G_IO_STATUS_ERROR
. This may be useful in the case of
G_CONVERT_ERROR_ILLEGAL_SEQUENCE
.
Returning one of these statuses from g_io_channel_read_line()
,
g_io_channel_read_line_string()
, or g_io_channel_read_to_end()
does not guarantee that the encoding can
be changed.
Channels which do not meet one of the above conditions cannot call
g_io_channel_seek_position()
with an offset of G_SEEK_CUR
, and, if
they are "seekable", cannot call g_io_channel_write_chars()
after
calling one of the API "read" functions.
|
a GIOChannel |
|
the encoding type |
|
location to store an error of type GConvertError |
Returns : |
G_IO_STATUS_NORMAL if the encoding was successfully set.
|
gboolean g_io_channel_get_close_on_unref (GIOChannel *channel);
Returns whether the file/socket/whatever associated with channel
will be closed when channel
receives its final unref and is
destroyed. The default value of this is TRUE
for channels created
by g_io_channel_new_file()
, and FALSE
for all other channels.
|
a GIOChannel. |
Returns : |
Whether the channel will be closed on the final unref of the GIOChannel data structure. |
void g_io_channel_set_close_on_unref (GIOChannel *channel, gboolean do_close);
Setting this flag to TRUE
for a channel you have already closed
can cause problems.
|
a GIOChannel |
|
Whether to close the channel on the final unref of
the GIOChannel data structure. The default value of
this is TRUE for channels created by g_io_channel_new_file() ,
and FALSE for all other channels.
|
GIOError g_io_channel_read (GIOChannel *channel, gchar *buf, gsize count, gsize *bytes_read);
g_io_channel_read
has been deprecated since version 2.2 and should not be used in newly-written code. Use g_io_channel_read_chars()
instead.
Reads data from a GIOChannel.
|
a GIOChannel |
|
a buffer to read the data into (which should be at least count bytes long) |
|
the number of bytes to read from the GIOChannel |
|
returns the number of bytes actually read |
Returns : |
G_IO_ERROR_NONE if the operation was successful.
|
typedef enum { G_IO_ERROR_NONE, G_IO_ERROR_AGAIN, G_IO_ERROR_INVAL, G_IO_ERROR_UNKNOWN } GIOError;
GIOError is only used by the deprecated functions g_io_channel_read()
,
g_io_channel_write()
, and g_io_channel_seek()
.
GIOError g_io_channel_write (GIOChannel *channel, const gchar *buf, gsize count, gsize *bytes_written);
g_io_channel_write
has been deprecated since version 2.2 and should not be used in newly-written code. Use g_io_channel_write_chars()
instead.
Writes data to a GIOChannel.
|
a GIOChannel |
|
the buffer containing the data to write |
|
the number of bytes to write |
|
the number of bytes actually written |
Returns : |
G_IO_ERROR_NONE if the operation was successful.
|
GIOError g_io_channel_seek (GIOChannel *channel, gint64 offset, GSeekType type);
g_io_channel_seek
has been deprecated since version 2.2 and should not be used in newly-written code. Use g_io_channel_seek_position()
instead.
Sets the current position in the GIOChannel, similar to the standard
library function fseek()
.
|
a GIOChannel |
|
an offset, in bytes, which is added to the position specified
by type
|
|
the position in the file, which can be G_SEEK_CUR (the current
position), G_SEEK_SET (the start of the file), or G_SEEK_END
(the end of the file)
|
Returns : |
G_IO_ERROR_NONE if the operation was successful.
|
void g_io_channel_close (GIOChannel *channel);
g_io_channel_close
has been deprecated since version 2.2 and should not be used in newly-written code. Use g_io_channel_shutdown()
instead.
Close an IO channel. Any pending data to be written will be
flushed, ignoring errors. The channel will not be freed until the
last reference is dropped using g_io_channel_unref()
.
|
A GIOChannel |
|
Convenience functions for creating GIOChannel instances and adding them to the main event loop. |