[Gegl-developer] geglbuffer-add-image writes GeglBuffer to disk only after a gegl_buffer_flush()?

[Giuseppe Rota]

Hi all,
I'm just starting to learn gegl, so please forgive my lack of
knowledge. I started to read the autogenerated docs and the code from
the "examples" subdir.
I got stuck with the geglbuffer-add-image example, though.
I expected to find, after a successful run, a file (first argument)
containing the serialization (or dump, if you will) of a GeglBuffer (I
used data/surfer.png as input).
That did not happen so I inserted a gegl_buffer_flush(buffer);
instruction before the 2 g_object_unref near the end of the main().
That did the trick, I now have a binary file with the serialization of
a GeglBuffer (first 4 bytes are "GEGL").
This happens (on Linux) both with version 0.0.22 and with the HEAD svn
version (both babl and gegl) (GIO enabled).

Can you please explain the rationale behind this behaviour?

On a unrelated note, what's the difference between gegl_buffer_load
and gegl_buffer_open?