From dcaa58744e75305b28b8dd4bbe6a40c4a1c9d0c1 Mon Sep 17 00:00:00 2001
From: Benoit Jacob <jacob.benoit.1@gmail.com>
Date: Mon, 19 Jan 2009 13:23:41 +0000
Subject: [PATCH] #error if min or max is defined

---
 Eigen/Core | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Eigen/Core b/Eigen/Core
index 7f42a6c29..211e0f9c7 100644
--- a/Eigen/Core
+++ b/Eigen/Core
@@ -69,6 +69,13 @@
   #include <new>
 #endif
 
+// this needs to be done after all possible windows C header includes and before any Eigen source includes
+// (system C++ includes are supposed to be able to deal with this already):
+// windows.h defines min and max macros which would make Eigen fail to compile.
+#if defined(min) || defined(max)
+#error The preprocessor symbols 'min' or 'max' are defined. If you are compiling on Windows, do #define NOMINMAX to prevent windows.h from defining these symbols.
+#endif
+
 namespace Eigen {
 
 /** \defgroup Core_Module Core module