<div dir="ltr">This is a very informative response that should be incorporated into to Gstreamer's application development manual.</div><div class="gmail_extra"> <div class="gmail_quote">2015-01-09 10:02 GMT+01:00 Sebastian Dröge <<a href="mailto:sebastian@centricular.com" target="_blank">sebastian@centricular.com</a>>: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On Di, 2015-01-06 at 18:10 -0800, hxpax wrote: > That could be a big problem on some other platforms, more than just a > segfault. It could result in worse situations, yes. > I wonder are there any conventions for unref? The docs would tell you, they now have annotations on parameters and return values hopefully everywhere. Like (transfer none), (transfer full), (transfer container) and (transfer floating). none: for return values you don't own it and must not unref it, for parameters you still own it and must unref it full: for return values you own it and must unref it, for parameters you don't own it anymore and must get another reference with ref before passing it to the function if you still need it afterwards container: only used for containers, e.g. lists. Means the same as transfer full for the actual container, but transfer none for the elements of the container floating: tricky one, check the documentation for floating references first. It means for return values that you get a floating reference, for parameters it means that it is transfer full for floating references and transfer none for non-floating references. General rule is that setter should be transfer none, getter transfer full, adder (e.g. gst_bin_add()) transfer full or transfer floating. Exception for getters (and things like gst_message_parse_*) are things like GstStructure, GstMessage, etc where the return value is transfer none and stays valid as long as you have a reference to its container. Functions that take a const pointer or return one are by definition transfer none. Things that pass buffers/messages/events on to other pads/elements are transfer full (e.g. gst_pad_push(), gst_element_post_message()), query related things are transfer none. Reason is that you usually want to get rid of the references of the former when passing it (also to keep buffers writable downstream if possible), while for queries you still want to own the reference (how would you otherwise get the query result later?). Unfortunately there are a few inconsistencies and exceptions to these rules. Hope this helps! -- Sebastian Dröge, Centricular Ltd · <a href="http://www.centricular.com" target="_blank">http://www.centricular.com</a> _______________________________________________ gstreamer-devel mailing list <a href="mailto:gstreamer-devel@lists.freedesktop.org">gstreamer-devel@lists.freedesktop.org</a> <a href="http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel" target="_blank">http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel</a> </blockquote></div> </div>