Varargs macros subtly broken

[Jamie Lokier]

Neil Booth wrote:
> > For other tokens, perhaps C99 requires that the token preceding
> > ##__VA_ARGS__ is not deleted, if it is possible to paste them?
> 
> C99 has no concept of token deletion like this at all.  It's purely an
> extension.

Precisely the reason we why should not, in general, delete tokens.

However deleting the comma may be permitted by the standard precisely
because you can't paste a comma with another token anyway.  Hmm.

I wonder what happens to argument prescan of __VA_ARGS__ in the presence
of ##.

-- Jamie