Guard headers tool.
diff --git a/include/grpc/byte_buffer_reader.h b/include/grpc/byte_buffer_reader.h
index 4446e0c..cb757cf 100644
--- a/include/grpc/byte_buffer_reader.h
+++ b/include/grpc/byte_buffer_reader.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_BYTE_BUFFER_READER_H__
-#define __GRPC_BYTE_BUFFER_READER_H__
+#ifndef GRPC_BYTE_BUFFER_READER_H
+#define GRPC_BYTE_BUFFER_READER_H
 
 #include <grpc/grpc.h>
 #include <grpc/byte_buffer.h>
@@ -46,4 +46,4 @@
   } current;
 };
 
-#endif /* __GRPC_BYTE_BUFFER_READER_H__ */
+#endif  /* GRPC_BYTE_BUFFER_READER_H */