[Libc++] Use #pragma push_macro/pop_macro to better handle min/max on Windows
Summary:
This patch improves how libc++ handles min/max macros within the headers. Previously libc++ would undef them and emit a warning.
This patch changes libc++ to use `#pragma push_macro` to save the macro before undefining it, and `#pragma pop_macro` to restore the macros and the end of the header.
Reviewers: mclow.lists, bcraig, compnerd, EricWF
Reviewed By: EricWF
Subscribers: cfe-commits, krytarowski
Differential Revision: https://reviews.llvm.org/D33080
llvm-svn: 304357
diff --git a/libcxx/include/istream b/libcxx/include/istream
index 530f204..0b8e05d 100644
--- a/libcxx/include/istream
+++ b/libcxx/include/istream
@@ -162,12 +162,14 @@
#include <__config>
#include <ostream>
-#include <__undef_min_max>
-
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
_LIBCPP_BEGIN_NAMESPACE_STD
template <class _CharT, class _Traits>
@@ -1683,4 +1685,6 @@
_LIBCPP_END_NAMESPACE_STD
+_LIBCPP_POP_MACROS
+
#endif // _LIBCPP_ISTREAM