Documenting use of canonical paths in external APIs

On Wed, 11 Apr 2007, Hyrum K. Wright wrote:

> Daniel Rall wrote:
...
> > I asked Erik where we document this important API usage fact, but he
> > wasn't sure. Do we document this anywhere? If not, I suggest
> > documenting it in hacking.html.
>
> Would documenting it in the header files also be useful? After all, it
> is something which the API consumers should be aware of. The header
> files are what outlines our API specification, and this seems part of
> that spec.

I first thought of the header files (I'd personally like to see it
documented there). I suppose a sweep through svn_client.h would be a
sufficient, combined with a note in hacking.html?