diff --git a/src/Network/GRPC/Constants.hsc b/src/Network/GRPC/Constants.hsc
index 1642fca..406fa47 100644
--- a/src/Network/GRPC/Constants.hsc
+++ b/src/Network/GRPC/Constants.hsc
@@ -2,8 +2,13 @@ module Network.GRPC.Constants where
 
 #include "grpc/grpc.h"
 
+argEnableCensus :: Int
 argEnableCensus = #const GRPC_ARG_ENABLE_CENSUS
+
+argMaxConcurrentStreams :: Int
 argMaxConcurrentStreams = #const GRPC_ARG_MAX_CONCURRENT_STREAMS
+
+argMaxMessageLength :: Int
 argMaxMessageLength = #const GRPC_ARG_MAX_MESSAGE_LENGTH
 
 writeBufferHint :: Int