diff --git a/include/istream b/include/istream
index e882e70f..47631ba2 100644
--- a/include/istream
+++ b/include/istream
@@ -199,12 +199,12 @@ protected:
     void swap(basic_istream& __rhs);
 
 #ifndef _LIBCPP_HAS_NO_DELETED_FUNCTIONS
-    basic_istream           (basic_istream& __rhs) = delete;
-    basic_istream& operator=(basic_istream& __rhs) = delete;
+    basic_istream           (const basic_istream& __rhs) = delete;
+    basic_istream& operator=(const basic_istream& __rhs) = delete;
 #else
 private:
-    basic_istream           (basic_istream& __rhs);
-    basic_istream& operator=(basic_istream& __rhs);
+    basic_istream           (const basic_istream& __rhs);
+    basic_istream& operator=(const basic_istream& __rhs);
 #endif
 public:
 
diff --git a/include/ostream b/include/ostream
index 36f08617..2e27070f 100644
--- a/include/ostream
+++ b/include/ostream
@@ -179,12 +179,12 @@ protected:
     void swap(basic_ostream& __rhs);
 
 #ifndef _LIBCPP_HAS_NO_DELETED_FUNCTIONS
-    basic_ostream           (basic_ostream& __rhs) = delete;
-    basic_ostream& operator=(basic_ostream& __rhs) = delete;
+    basic_ostream           (const basic_ostream& __rhs) = delete;
+    basic_ostream& operator=(const basic_ostream& __rhs) = delete;
 #else
 private:
-    basic_ostream           (basic_ostream& __rhs);
-    basic_ostream& operator=(basic_ostream& __rhs);
+    basic_ostream           (const basic_ostream& __rhs);
+    basic_ostream& operator=(const basic_ostream& __rhs);
 #endif
 public: