Re: [dpdk-dev] [PATCHv3 3/3] ABI: Add some documentation

[Neil Horman <nhorman@tuxdriver.com>]

On Sun, Jun 28, 2015 at 10:24:42PM +0200, Thomas Monjalon wrote:
> 2015-06-26 10:54, Neil Horman:
> > On Fri, Jun 26, 2015 at 03:00:17PM +0200, Thomas Monjalon wrote:
> > > 2015-06-25 10:35, Neil Horman:
> > > > +* ``VERSION_SYMBOL(b, e, n)``: Creates a symbol version table entry binding
> > > > +  unversioned symbol ``b`` to the internal function ``b_e``.
> > > 
> > > Should a versioned symbol <b>@DPDK_<n>
> > > 
> > Sure.
> 
> When fixed, this series can be applied.
> 
> > > > +* ``BASE_SYMBOL(b, e)``: Creates a symbol version table entry binding
> > > > +  unversioned symbol ``b`` to the internal function ``b_e``.
> > > 
> > > Please give a use case of BASE_SYMBOL.
> > > 
> > No, I'd rather remove it if you really insist.  As noted before the way we set
> > up the version map files means we currently have no need for this particular
> > directive.  I only included it for completeness.  I think an example use in
> > light of that fact would only confuse people.  If you're going to draw a line in
> > the sand around it, I'll just remove it.
> 
> No line in the sand, but it seems better to remove it to avoid confusing people.
> ABI compat is already enough difficult to understand ;)
> 
> > > [...]
> > > > +The addition of the new block tells the linker that a new version node is
> > > > +available (DPDK_2.1), which contains the symbol rte_acl_create, and inherits the
> > > > +symbols from the DPDK_2.0 node.
> > > 
> > > which contains the old version of the symbol rte_acl_create
> > > 
> > I don't understand, is it not obvious that the DPDK_2.0 node contains the 2.0
> > version of the symbol and the DPDK_2.1 node contains the 2.1 version of the
> > symbol?
> 
> Yes it is.
> I thought it was needed to insist on the existence of a new symbol while the
> old one still exists. Just trying to be didactic.
> 
Ah, no its not a mandate (though doing so is an optional aproach, which trades
off the need to use MAP_STATIC_SYMBOL for the maintain a public symbol with the
same name).  I can include an alternate example of the same exercize that
follows that approach, but given our time contraints would rather to that in a
follow up patch series


Neil