File.openReadwrite

Opens an existing file for reading and writing. The result is a #GFileIOStream that can be used to read and write the contents of the file.

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 [gio.types.IOErrorEnum.Cancelled] will be returned.

If the file does not exist, the [gio.types.IOErrorEnum.NotFound] error will be returned. If the file is a directory, the [gio.types.IOErrorEnum.IsDirectory] error will be returned. Other errors are possible too, and depend on what kind of filesystem the file is on. Note that in many non-local file cases read and write streams are not supported, so make sure you really need to do read and write streaming, rather than just opening for reading or writing.