Re: [Vala] Can adding new virtual method break ABI?

[Luca Bruno <lethalman88 gmail com>]

2011/12/11 Tal Hadad <tal_hd hotmail com>

>  > Yes it does. What C programmers often do is adding unused vfuncs as
> padding for future extension of the class. From this perspective Vala could
> theoretically add some kind of padding to avoid abi breakage.
> So what about this idea for fix it:
> Create a new attribute property in [CCode], named binary_position, that is
> used for virtual methods, but can be used for another things(such as
> fields, etc.).
> It can be used by the developer to avoid this risk, by doing so:
> Every time the developer create a new virtual method, he shell pick the
> smallest number available for virtual method position, and put it in
> binary_position in [CCode].
> On every planned ABI(&API) break, he can minimize those binary_position(s)
> for virtual methods.
>
> This idea is based on the assumption that the size of XClass struct
> doesn't matter and can be changed(Am I right?).
> Also, how does the virtual method order is currently done by Vala? Is it
> alphabetic or by the order of the decelerations?

The ordering does not matter, the padding does.

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