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Re: RFC: PATCH to allow passing non-trivial types through ...
- From: Nathan Sidwell <nathan at codesourcery dot com>
- To: Jason Merrill <jason at redhat dot com>, gcc-patches List <gcc-patches at gcc dot gnu dot org>, Jonathan Wakely <jwakely dot gcc at gmail dot com>, Paolo Carlini <paolo dot carlini at oracle dot com>
- Date: Mon, 11 Aug 2014 22:23:31 -0700
- Subject: Re: RFC: PATCH to allow passing non-trivial types through ...
- Authentication-results: sourceware.org; auth=none
- References: <53E92F6C dot 5050808 at redhat dot com>
On 08/11/14 14:02, Jason Merrill wrote:
A customer was recently complaining about G++ rejecting code that tries to pass
a type with a non-trivial copy constructor through ..., which is undefined in
C++98 and conditionally-supported in C++11. In GCC 3.1 and below we gave a
warning and then did a bitwise copy. From GCC 3.2 to 4.4 we gave a warning and
then aborted at runtime. From 4.5 on we have just given an error.
On considering the request, it occurred to me that we could handle variadic
arguments of non-trivial types the same way we handle normal value arguments of
such types: pass by invisible reference. So this patch implements that. Since
it's been so long since this was allowed at all, I don't think we need to worry
about ABI incompatibility with the 3.1 behavior.
Thoughts?
Sounds sensible to me.
nathan
--
Nathan Sidwell