This is the mail archive of the gcc@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: Deprecating arithmetic on std::atomic<void*>


On Thu, 20 Apr 2017, Florian Weimer wrote:

On 04/19/2017 07:07 PM, Jonathan Wakely wrote:
I know it's a bit late, but I'd like to propose deprecating the
libstdc++ extension that allows arithmetic on std::atomic<void*>.
Currently we make it behave like arithmetic on void*, which is also a
GNU extension (https://gcc.gnu.org/onlinedocs/gcc/Pointer-Arith.html).
We also allow arithmetic on types such as std::atomic<void(*)()> which
is probably not useful (PR 69769).

Why is it acceptable to have the extension for built-in types, but not for library types wrapping them? Why be inconsistent about this?

I thought the extension was there for legacy code, to avoid breaking old programs, and we could deprecate it eventually. At least the manual is missing an example of where this extension is actually useful. For atomic, I don't see why we should encourage people to write new code that violates the standard...

--
Marc Glisse


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]