Garrett Rooney <rooneg@electricjellyfish.net> writes:
> > > + if (svn_path_is_url ((const svn_string_t *)path))
> >
> > This cast relies on the members of svn_string_t being ordered the same
> > as svn_stringbuf_t. It's true at present, but is it guaranteed?
>
> that's one of the things i was wondering. if it is guaranteed, it
> would be quite useful, as one can do what i just did, and pass
> stringbufs to functions that take const string_t *'s. if this is
> guaranteed, we should probably document it though.
Even if they are ordered the same (which I believe is guaranteed),
they may not be padded the same. Structure members may be padded for
alignment purposes, therefore a cast like this is technically not
valid.
I mean, *probably* it would work on every platform, because the first
two members of both structs are the same type, and one would imagine
that all alignment algorithms do a single left-to-right pass. But we
shouldn't count on this, that's getting really edgy. :-)
Instead, why not just declare a local svn_string_t variable and
manually set its `data' and `len' fields to be the same as `path's?
-Karl
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Received on Sat Oct 21 14:36:57 2006