diff --git a/libcpp/ChangeLog b/libcpp/ChangeLog
index 8013364e6be..64ed4683669 100644
--- a/libcpp/ChangeLog
+++ b/libcpp/ChangeLog
@@ -1,5 +1,8 @@
 2011-10-31  Jason Merrill  <jason@redhat.com>
 
+	PR libstdc++/1773
+	* init.c (cpp_init_builtins): Set __cplusplus for C++11.
+
 	PR c++/50920
 	* include/cpplib.h (enum c_lang): Rename CLK_CXX0X to CLK_CXX11,
 	CLK_GNUCXX0X to CLK_GNUCXX11.
diff --git a/libcpp/init.c b/libcpp/init.c
index bbaa8ae10c3..9101b34e086 100644
--- a/libcpp/init.c
+++ b/libcpp/init.c
@@ -461,7 +461,13 @@ cpp_init_builtins (cpp_reader *pfile, int hosted)
     _cpp_define_builtin (pfile, "__STDC__ 1");
 
   if (CPP_OPTION (pfile, cplusplus))
-    _cpp_define_builtin (pfile, "__cplusplus 199711L");
+    {
+      if (CPP_OPTION (pfile, lang) == CLK_CXX11
+	   || CPP_OPTION (pfile, lang) == CLK_GNUCXX11)
+	_cpp_define_builtin (pfile, "__cplusplus 201103L");
+      else
+	_cpp_define_builtin (pfile, "__cplusplus 199711L");
+    }
   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)