On Sat, Mar 3, 2012 at 4:51 AM, Daniel James <dnljms@gmail.com> wrote:
On 1 March 2012 23:34, Jeffrey Lee Hellrung, Jr. <jeffrey.hellrung@gmail.com> wrote:
I think the important distinction is
"BOOST_NO_INITIALIZER_LISTS is probably useless as it only indicates compiler support and initializer lists can't really be used without the header."
I wasn't sure whether initializer lists required a header, so I agree
with
Daniel that it's probably redundant.
I was wrong, C++11 added other uses which don't require the header. Although I don't think portable code would ever need to take advantage of that.
The situation with the visual c++ 10 beta was that initializer lists weren't supported, but the header was present. In that case BOOST_NO_INITIALIZER_LISTS would be defined, but BOOST_NO_0X_HDR_INITIALIZER_LISTS would not. A compiled library might still want to define methods which take initializer lists so that they can be used when linking with a different compiler that does support them.
If you look at unordered, it now uses BOOST_NO_0X_HDR_INITIALIZER_LISTS in the headers (they support std::initializer_list but don't ever create one), but BOOST_NO_INITIALIZER_LISTS for test cases that actually use an initializer list.
But.... it looks like including the header in Visual C++ 10 was actually a mistake:
http://connect.microsoft.com/VisualStudio/feedback/details/533464/the-initia...
LOL...nice.
It's also confusing having the two macros, very easy to get wrong, and the potential use cases are pretty dubious.
I'll ultimately defer to your and others' judgements here. Let me just say that it does sound like an argument can be made to continue to use BOOST_NO_INITIALIZER_LISTS (indicating whether the compiler correctly implements and supports (including header support) initializer lists) rather than BOOST_NO_0X_HDR_INITIALIZER_LISTS (header is present and...well who knows what else? should it only be undefined in the former case for BOOST_NO_INITIALIZER_LISTS?). The former macro is also more succinct. - Jeff