From 4a40b3785dc81112856d517676dbcfa9204e16df Mon Sep 17 00:00:00 2001
From: Christian von Schultz <christian.git@vonschultz.se>
Date: Mon, 22 Oct 2018 21:14:40 +0200
Subject: [PATCH] Collapsed revision (based on pull request PR-325) * Support
 compiling without IO streams

Add the preprocessor definition EIGEN_NO_IO which, if defined,
disables all use of the IO streams part of the standard library.
---
 Eigen/Core                     | 8 ++++++--
 Eigen/src/Core/arch/GPU/Half.h | 2 ++
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/Eigen/Core b/Eigen/Core
index a4596e73b..0c09f7c79 100644
--- a/Eigen/Core
+++ b/Eigen/Core
@@ -72,7 +72,9 @@
 #include <cmath>
 #include <cassert>
 #include <functional>
-#include <iosfwd>
+#ifndef EIGEN_NO_IO
+  #include <iosfwd>
+#endif
 #include <cstring>
 #include <string>
 #include <limits>
@@ -224,7 +226,9 @@ using std::ptrdiff_t;
 #include "src/Core/util/IndexedViewHelper.h"
 #include "src/Core/util/ReshapedHelper.h"
 #include "src/Core/ArithmeticSequence.h"
-#include "src/Core/IO.h"
+#ifndef EIGEN_NO_IO
+  #include "src/Core/IO.h"
+#endif
 #include "src/Core/DenseCoeffsBase.h"
 #include "src/Core/DenseBase.h"
 #include "src/Core/MatrixBase.h"
diff --git a/Eigen/src/Core/arch/GPU/Half.h b/Eigen/src/Core/arch/GPU/Half.h
index 65b38bbfb..f87d8a18c 100644
--- a/Eigen/src/Core/arch/GPU/Half.h
+++ b/Eigen/src/Core/arch/GPU/Half.h
@@ -607,10 +607,12 @@ EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC half (max)(const half& a, const half& b) {
 #endif
 }
 
+#ifndef EIGEN_NO_IO
 EIGEN_ALWAYS_INLINE std::ostream& operator << (std::ostream& os, const half& v) {
   os << static_cast<float>(v);
   return os;
 }
+#endif
 
 } // end namespace half_impl