[PATCH] D139266: Headers: tweak inclusion condition for stdatomic.h

[Saleem Abdulrasool via Phabricator via cfe-commits]

compnerd created this revision.
compnerd added reviewers: aaron.ballman, Mordante, fsb4000.
Herald added a project: All.
compnerd requested review of this revision.
Herald added a project: clang.

MSVC requires that C++23 be available (`_HAS_CXX23`) else the entire
content is elided.  Conditionalise the inclusion properly so that C/C++
code using `stdatomic.h` for `memory_order_*` constants are able to do
so without changing the C++ standard.  This repairs builds of Swift and
libdispatch after ba49d39b20cc5358da28af2ac82bd336028780bc <https://reviews.llvm.org/rGba49d39b20cc5358da28af2ac82bd336028780bc>.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D139266

Files:
  clang/lib/Headers/stdatomic.h


Index: clang/lib/Headers/stdatomic.h
===================================================================
--- clang/lib/Headers/stdatomic.h
+++ clang/lib/Headers/stdatomic.h
@@ -17,8 +17,8 @@
  * explicitly disallows `stdatomic.h` in the C mode via an `#error`.  Fallback
  * to the clang resource header until that is fully supported.
  */
-#if __STDC_HOSTED__ &&                                                         \
-    __has_include_next(<stdatomic.h>) && !(defined(_MSC_VER) && !defined(__cplusplus))
+#if __STDC_HOSTED__ && __has_include_next(<stdatomic.h>)                        \
+    && !(defined(_MSC_VER) && __cplusplus-0 < 202002l)
 # include_next <stdatomic.h>
 #else
 


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