GFileOutputStream

GFileOutputStream — File output streaming operations

Synopsis


#include <gio/gio.h>

                    GFileOutputStream;
GFileInfo *         g_file_output_stream_query_info     (GFileOutputStream *stream,
                                                         const char *attributes,
                                                         GCancellable *cancellable,
                                                         GError **error);
void                g_file_output_stream_query_info_async
                                                        (GFileOutputStream *stream,
                                                         const char *attributes,
                                                         int io_priority,
                                                         GCancellable *cancellable,
                                                         GAsyncReadyCallback callback,
                                                         gpointer user_data);
GFileInfo *         g_file_output_stream_query_info_finish
                                                        (GFileOutputStream *stream,
                                                         GAsyncResult *result,
                                                         GError **error);
char *              g_file_output_stream_get_etag       (GFileOutputStream *stream);

Object Hierarchy

  GObject
   +----GOutputStream
         +----GFileOutputStream

Implemented Interfaces

GFileOutputStream implements GSeekable.

Description

GFileOutputStream provides output streams that write their content to a file.

GFileOutputStream implements GSeekable, which allows the output stream to jump to arbitrary positions in the file and to truncate the file, provided the filesystem of the file supports these operations. In addition to the generic g_seekable_ API, GFileOutputStream has its own API for seeking and positioning. To find the position of a file output stream, use g_file_output_stream_tell(). To find out if a file output stream supports seeking, use g_file_output_stream_can_seek(). To position a file output stream, use g_file_output_stream_seek(). To find out if a file output stream supports truncating, use g_file_output_stream_can_truncate(). To truncate a file output stream, use g_file_output_stream_truncate().

Details

GFileOutputStream

typedef struct _GFileOutputStream GFileOutputStream;

A subclass of GOutputStream for opened files. This adds a few file-specific operations and seeking and truncating.

GFileOutputStream implements GSeekable.

g_file_output_stream_query_info ()

GFileInfo *         g_file_output_stream_query_info     (GFileOutputStream *stream,
                                                         const char *attributes,
                                                         GCancellable *cancellable,
                                                         GError **error);

Queries a file output stream for the given attributes. This function blocks while querying the stream. For the asynchronous version of this function, see g_file_output_stream_query_info_async(). While the stream is blocked, the stream will set the pending flag internally, and any other operations on the stream will fail with G_IO_ERROR_PENDING.

Can fail if the stream was already closed (with error being set to G_IO_ERROR_CLOSED), the stream has pending operations (with error being set to G_IO_ERROR_PENDING), or if querying info is not supported for the stream's interface (with error being set to G_IO_ERROR_NOT_SUPPORTED). In all cases of failure, NULL will be returned.

If cancellable is not NULL, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error G_IO_ERROR_CANCELLED will be set, and NULL will be returned.

stream :

 a GFileOutputStream.

attributes :

 a file attribute query string.

cancellable :

 optional GCancellable object, NULL to ignore.

error :

 a GError, NULL to ignore.

Returns :

 a GFileInfo for the stream, or NULL on error.

g_file_output_stream_query_info_async ()

void                g_file_output_stream_query_info_async
                                                        (GFileOutputStream *stream,
                                                         const char *attributes,
                                                         int io_priority,
                                                         GCancellable *cancellable,
                                                         GAsyncReadyCallback callback,
                                                         gpointer user_data);

Asynchronously queries the stream for a GFileInfo. When completed, callback will be called with a GAsyncResult which can be used to finish the operation with g_file_output_stream_query_info_finish().

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

stream :

 a GFileOutputStream.

attributes :

 a file attribute query string.

io_priority :

 the I/O priority of the request.

cancellable :

 optional GCancellable object, NULL to ignore.

callback :

 callback to call when the request is satisfied

user_data :

 the data to pass to callback function

g_file_output_stream_query_info_finish ()

GFileInfo *         g_file_output_stream_query_info_finish
                                                        (GFileOutputStream *stream,
                                                         GAsyncResult *result,
                                                         GError **error);

Finalizes the asynchronous query started by g_file_output_stream_query_info_async().

stream :

 a GFileOutputStream.

result :

 a GAsyncResult.

error :

 a GError, NULL to ignore.

Returns :

 A GFileInfo for the finished query.

g_file_output_stream_get_etag ()

char *              g_file_output_stream_get_etag       (GFileOutputStream *stream);

Gets the entity tag for the file when it has been written. This must be called after the stream has been written and closed, as the etag can change while writing.

stream :

 a GFileOutputStream.

Returns :

 the entity tag for the stream.

See Also

#GOutputStream, GDataOutputStream, GSeekable
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