<div dir="ltr"><div>Thank you, </div>m. </div><div class="gmail_extra"> <div class="gmail_quote">2016-05-23 21:03 GMT+02:00 Simon McVittie <<a href="mailto:simon.mcvittie@collabora.co.uk" target="_blank">simon.mcvittie@collabora.co.uk</a>>: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On 23/05/16 19:46, <a href="mailto:marcin@saepia.net">marcin@saepia.net</a> wrote: > the array length is not aligned to 8 bytes, but to 4 bytes. But type of > this array is struct, which according to the specification should always > align to 8 bytes. The header field array isn't a struct, it's an array (which happens to contain structs). The array length is a 4-byte integer, so it's aligned to a multiple of 4 bytes. After the length, there are some number of structs, and *those* are aligned to a multiple of 8 bytes. In effect, the beginning of every message looks like this: bytes 0-3: header start, four 1-byte quantities 4-7: body length 8-11: serial No padding, 12 is already a multiple of 4 12-15: header field array length No padding, 16 is already a multiple of 8 16+: first header field struct Let's say the first header field struct happens to be 13 bytes long. We'd continue as follows: 16-28: first header field struct 29-31: 3 bytes of padding to reach next multiple of 8 32+: second header field struct (Yes, this means the marshalling for `a(whatever)`, an array of structs, is not the same as the marshalling for `(a(whatever))`, a struct containing a single array of structs. There's no particular reason, it's just how this stuff was designed 10+ years ago.) Regards, S -- Simon McVittie Collabora Ltd. <<a href="http://www.collabora.com/" rel="noreferrer" target="_blank">http://www.collabora.com/</a>> _______________________________________________ dbus mailing list <a href="mailto:dbus@lists.freedesktop.org">dbus@lists.freedesktop.org</a> <a href="https://lists.freedesktop.org/mailman/listinfo/dbus" rel="noreferrer" target="_blank">https://lists.freedesktop.org/mailman/listinfo/dbus</a> </blockquote></div> </div>