[libvirt] version script and non-existent symbols

[Daniel P. Berrange]

On Sat, Dec 13, 2008 at 05:03:33PM +0000, John Levon wrote:
> 
> The current version script refers to symbols that don't exist in the
> code. What is the purpose of this? The Solaris linker (quite correctly,
> I think) generates hanging references to such symbols.

That's a bug - can you tell me which you see as missing. We can
just remove them.

> But there is another more basic problem. If I configure out various
> components, such as storage, which is necessary in order to compile,
> then /those/ symbols don't exist, and the build fails as above.
> 
> I think the solution to the latter is to provide stubs that return
> failure codes for every symbol that can be ./configured out. So we'd
> introduce a stubs.c file that has these for everything, and compile each
> of the stubs if the relevant WITH_ option isn't set.

I think I'd be more inclined to split up the libvirt_sym.version.in
file into pieces, one providing all the public API symbols, which
would never change. Then for all the private symbols have them in
a file matching the source file, eg for domain_conf.h, have a file
domain_conf.sym.  Finally have a rule to merge all the .sym files
using the same #ifdef as we use to turn on/off various files

eg, 

   libvirt_SYMBOLS = libvirt_public.sym

   if WITH_XEN
   libvirt_SYMBOLS += xen_internal.sym xend_internal.sym
   endif

   if WITH_STORAGE
   libvirt_SYMBOLS += storage_conf.sym
   end

> Finally, C-style comments aren't supported with the Solaris linker.
> Since both linkers support # as a comment delimiter, any objections to
> changing it to do that?

Fine by me. # is nicer anyway because you don't have to remember
to terminate it :-)

Daniel
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