EricWF added inline comments. ================ Comment at: include/atomic:859 @@ +858,3 @@ +template <> _LIBCPP_CONSTEXPR bool __libcpp_always_lock_free<char32_t> = 2 == ATOMIC_CHAR32_T_LOCK_FREE; +template <> _LIBCPP_CONSTEXPR bool __libcpp_always_lock_free<wchar_t> = 2 == ATOMIC_WCHAR_T_LOCK_FREE; +template <> _LIBCPP_CONSTEXPR bool __libcpp_always_lock_free<short> = 2 == ATOMIC_SHORT_LOCK_FREE; ---------------- jfb wrote: > EricWF wrote: > > jfb wrote: > > > bcraig wrote: > > > > Do we need to support configurations were wchar_t is a typedef to an > > > > integer type, or is that an abomination too painful to deal with? > > > > > > > > I have no idea if the rest of libcxx attempts to deal with wchar_t > > > > typedefs. > > > Do you have examples of such platforms? The standard is pretty clear that > > > they're wrong: > > > > > > > [basic.fundamental] > > > > > > > > Type `wchar_t` is a distinct type whose values can represent distinct > > > > codes for all members of the largest extended character set specified > > > > among the supported locales. Type `wchar_t` shall have the same size, > > > > signedness, and alignment requirements as one of the other integral > > > > types, called its *underlying type*. > > > > > > I'll defer to @mclow.lists on whether we can about such implementations > > > or not. > > I don't think we have to deal with such typedefs for `wchar_t` but we do > > have to deal with non-sense typedefs (that we unfortunately supply) for > > `char16_t` and `char32_t` in C++03 mode with GCC. > > > > And our <atomic> implementation needs to compile in C++03 (Sorry, I did > > that). > `__cpp_lib_atomic_is_always_lock_free` takes care of it: it's only defined in > C++17 and later so `<atomic>` should compile just fine. > > Is there a test that would catch C++03 breakage? Ah I didn't realize that. We have a C++03 bot that will catch any breakage but if your only exposing this in C++17 then we are fine.
================ Comment at: include/atomic:898 @@ -834,1 +897,3 @@ +#if defined(__cpp_lib_atomic_is_always_lock_free) +# if defined(_LIBCPP_LOCK_FREE_IS_SIZE_BASED) ---------------- jfb wrote: > EricWF wrote: > > @mclow.lists I'm fine exposing this typedef retroactively in C++11 and > > earlier. Do you have any objections to that? > Which typedef do you mean? Looks like phabricator may have tagged the wrong > line. Sorry I haven't had my coffee yet :-S. I meant the "is_always_lock_free" variable. IDK why I said typedef. However I missed that this is already only exposed in C++17 and beyond. That's even better. ================ Comment at: test/std/atomics/atomics.lockfree/lockfree.pass.cpp:66 @@ +65,3 @@ + +// structs and unions can't be defined in the template invocation. +// Work around this with a typedef. ---------------- This needs to be guarded by `#if TEST_STD_VER > 14`. The macro lives in `test_macros.h`. http://reviews.llvm.org/D17951 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits