diff --git a/include/grpc++/impl/codegen/core_codegen.h b/include/grpc++/impl/codegen/core_codegen.h
index 9699abfb438725fb6fbe3f1454820c59c36a1711..2586b94504801ac467d597bf44d64fb7f8ae6656 100644
--- a/include/grpc++/impl/codegen/core_codegen.h
+++ b/include/grpc++/impl/codegen/core_codegen.h
@@ -31,6 +31,9 @@
  *
  */
 
+#ifndef GRPCXX_IMPL_CODEGEN_CORE_CODEGEN_H
+#define GRPCXX_IMPL_CODEGEN_CORE_CODEGEN_H
+
 // This file should be compiled as part of grpc++.
 
 #include <grpc++/impl/codegen/core_codegen_interface.h>
@@ -83,3 +86,5 @@ class CoreCodegen : public CoreCodegenInterface {
 };
 
 }  // namespace grpc
+
+#endif  // GRPCXX_IMPL_CODEGEN_CORE_CODEGEN_H
diff --git a/tools/distrib/check_include_guards.py b/tools/distrib/check_include_guards.py
index 56b2924a1ac5180ab06f13975bf4e3da8cb76271..28312813f65774aeacb34d7b78c5fa2f6de6df74 100755
--- a/tools/distrib/check_include_guards.py
+++ b/tools/distrib/check_include_guards.py
@@ -200,6 +200,6 @@ validator = GuardValidator()
 
 for filename in filename_list:
   if filename in KNOWN_BAD: continue
-  ok = validator.check(filename, args.fix)
+  ok = ok and validator.check(filename, args.fix)
 
 sys.exit(0 if ok else 1)