Re: [Libvir] PATCH: 5/10: public auth callback API

[Daniel Veillard <veillard redhat com>]

On Tue, Dec 04, 2007 at 12:57:39PM +0000, Richard W.M. Jones wrote:
> Daniel P. Berrange wrote:
> > virConnectPtr           virConnectOpenAuth      (const char *name,
> > 						 virConnectAuthPtr auth,
> > 						 int flags);
> 
> I'm a fan of callers passing in the size of the structure (as they see 
> it).  Allows the structure to be expanded in future, and if done right 
> can allow both forwards and backwards compatibility.
> 
> cf: http://www.libvirt.org/html/libvirt-libvirt.html#virDomainInterfaceStats

  Hum, honnestly, that's not my preferred way. If you really think there
should be room for expansion, I would either:
   - add a version number to the structure and allocator/destructor
     functions as part of the API (prefered)
   - add padding at tyhe end of the structure which could allow 
     a future growth

adding the size of the structure as the argument moves the complexity away
from the library implementor to the library user, 

Daniel

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