Eric Niebler wrote:
On 10/8/2012 6:08 AM, Michel Morin wrote:
This is just a small note related to boost::result_of.
When BOOST_RESULT_OF_USE_DECLTYPE is defined, boost::result_of tries to use decltype-based implementation (regardless of the compiler's decltype support).
Surprisingly, in a C++03 mode, libc++ defines `decltype` using `__typeof__`:
Bug 12488 (WONTFIX): decltype can be used in C++03 with no errors, no warnings http://llvm.org/bugs/show_bug.cgi?id=12488
So, when used with libc++, boost::result_of can be used with BOOST_RESULT_OF_USE_DECLTYPE even in a C++03 mode.
Does __typeof__ have EXACTLY the same semantics as C++11 decltype?
No, it doesn't. I don't like the idea of defining `decltype` macro in libc++: #ifdef _LIBCPP_HAS_NO_DECLTYPE #define decltype(x) __typeof__(x) #endif I created the bug report to libc++, but it got WONTFIX. Regards, Michel