[libcxx-commits] [libcxx] [libc++] Don't declare pmr::polymorphic_allocator before C++17 (PR #120850)

[Nikolas Klauser via libcxx-commits]

https://github.com/philnik777 created https://github.com/llvm/llvm-project/pull/120850

Fixes #120790


>From 30676835fa5db42f6312872cf8884f2bc98c118c Mon Sep 17 00:00:00 2001
From: Nikolas Klauser <nikolasklauser at berlin.de>
Date: Sat, 21 Dec 2024 19:39:39 +0100
Subject: [PATCH] [libc++] Don't declare pmr::polymorphic_allocator before
 C++17

---
 libcxx/include/__fwd/memory_resource.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/libcxx/include/__fwd/memory_resource.h b/libcxx/include/__fwd/memory_resource.h
index d68b2c2b631543..ca9d3770945c81 100644
--- a/libcxx/include/__fwd/memory_resource.h
+++ b/libcxx/include/__fwd/memory_resource.h
@@ -15,6 +15,8 @@
 #  pragma GCC system_header
 #endif
 
+#if _LIBCPP_STD_VER >= 17
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 namespace pmr {
@@ -24,4 +26,6 @@ class _LIBCPP_AVAILABILITY_PMR _LIBCPP_TEMPLATE_VIS polymorphic_allocator;
 
 _LIBCPP_END_NAMESPACE_STD
 
+#endif // _LIBCPP_STD_VER >= 17
+
 #endif // _LIBCPP___FWD_MEMORY_RESOURCE_H