diff --git a/libcpp/ChangeLog b/libcpp/ChangeLog
index 4ee03638d15a..81b3a94bb50e 100644
--- a/libcpp/ChangeLog
+++ b/libcpp/ChangeLog
@@ -1,3 +1,8 @@
+2011-08-18  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
+
+	PR libstdc++/1773
+	* init.c (cpp_init_builtins): Define __cplusplus 19971L.
+
 2011-08-18  Joseph Myers  <joseph@codesourcery.com>
 
 	* include/cpplib.h (struct cpp_options): Fix typo.
diff --git a/libcpp/init.c b/libcpp/init.c
index 1cbb9dda2f05..93f12d0d71f8 100644
--- a/libcpp/init.c
+++ b/libcpp/init.c
@@ -455,7 +455,7 @@ cpp_init_builtins (cpp_reader *pfile, int hosted)
     _cpp_define_builtin (pfile, "__STDC__ 1");
 
   if (CPP_OPTION (pfile, cplusplus))
-    _cpp_define_builtin (pfile, "__cplusplus 1");
+    _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)