_GLIBCXX_COMPATIBILITY_CXX0X and hash<error_condition>

[Jonathan Wakely]

On 12 March 2017 at 11:46, Daniel Krügler wrote:
> Being working on
>
> http://cplusplus.github.io/LWG/lwg-defects.html#2686
>
> I stumbled across the conditional _GLIBCXX_COMPATIBILITY_CXX0X define
> used in <system_error> and tried to figure out what it actually stands
> for. I couldn't find a documentation for it, but given that the
> seemingly essential file libstdc++-v3/src/c++11/compatibility-c++0x.cc
> does not define any hash<error_condition>, my current guess it that
> its definition in <system_error> should *not* by written within the
> _GLIBCXX_COMPATIBILITY_CXX0X block where hash<error_code> is defined.
>
> Is that correct?

Bah, my phone sent text/html mail so it got rejected by the list.
Here's what I wrote:

Yes.

The macro is for retaining old symbols from previous GCC releases.
It's not relevant for new features.