Description GFileIOStream provides io streams that both read and write to the same file handle. GFileIOStream implements GSeekable, which allows the io stream to jump to arbitrary positions in the file and to truncate the file, provided the filesystem of the file supports these operations. To find the position of a file io stream, use g_seekable_tell(). To find out if a file io stream supports seeking, use g_seekable_can_seek(). To position a file io stream, use g_seekable_seek(). To find out if a file io stream supports truncating, use g_seekable_can_truncate(). To truncate a file io stream, use g_seekable_truncate(). The default implementation of all the GFileIOStream operations and the implementation of GSeekable just call into the same operations on the output stream.