diff --git a/Eigen/src/Core/util/Meta.h b/Eigen/src/Core/util/Meta.h
index d31e95411..df72a6911 100755
--- a/Eigen/src/Core/util/Meta.h
+++ b/Eigen/src/Core/util/Meta.h
@@ -531,4 +531,30 @@ bool not_equal_strict(const double& x,const double& y) { return std::not_equal_t
 
 } // end namespace Eigen
 
+// Define portable (u)int{32,64} types
+#if EIGEN_HAS_CXX11
+#include <cstdint>
+namespace Eigen {
+namespace numext {
+typedef std::uint32_t uint32_t;
+typedef std::int32_t  int32_t;
+typedef std::uint64_t uint64_t;
+typedef std::int64_t  int64_t;
+}
+}
+#else
+// Without c++11, all compilers able to compile Eigen also
+// provides the C99 stdint.h header file.
+#include <stdint.h>
+namespace Eigen {
+namespace numext {
+typedef ::uint32_t uint32_t;
+typedef ::int32_t  int32_t;
+typedef ::uint64_t uint64_t;
+typedef ::int64_t  int64_t;
+}
+}
+#endif
+
+
 #endif // EIGEN_META_H