From 14c5cff2eeb1454130b4313c8f22f1853c1f6acd Mon Sep 17 00:00:00 2001
From: Tim Blechmann <tim@klingt.org>
Date: Sat, 29 Nov 2014 11:43:36 +0100
Subject: [PATCH] thread: physical_concurrency - windows xp does not provide
 GetLogicalProcessorInformation

---
 src/win32/thread.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/win32/thread.cpp b/src/win32/thread.cpp
index ed2c10bf..5c789b65 100644
--- a/src/win32/thread.cpp
+++ b/src/win32/thread.cpp
@@ -529,11 +529,12 @@ namespace boost
 
     unsigned thread::physical_concurrency() BOOST_NOEXCEPT
     {
-#if BOOST_PLAT_WINDOWS_RUNTIME
+#if BOOST_PLAT_WINDOWS_RUNTIME                                    \
+    || ( BOOST_USE_WINAPI_VERSION <= BOOST_WINAPI_VERSION_WINXP ) \  // a bit too strict: Windows XP with SP3 would be sufficient
+    || ( defined(__MINGW32__) && !defined(__MINGW64__) )
         return hardware_concurrency();
 #else
         unsigned cores = 0;
-#if !(defined(__MINGW32__) || defined (__MINGW64__))
         DWORD size = 0;
 
         GetLogicalProcessorInformation(NULL, &size);
@@ -550,7 +551,6 @@ namespace boost
             if (buffer[i].Relationship == RelationProcessorCore)
                 ++cores;
         }
-#endif
         return cores;
 #endif
     }