diff --git a/server/red-channel-client.cpp b/server/red-channel-client.cpp
index 850047a5..76e38137 100644
--- a/server/red-channel-client.cpp
+++ b/server/red-channel-client.cpp
@@ -1452,12 +1452,12 @@ void RedChannelClient::pipe_add_empty_msg(int msg_type)
     pipe_add(new_empty_msg(msg_type));
 }
 
-gboolean RedChannelClient::pipe_is_empty()
+bool RedChannelClient::pipe_is_empty() const
 {
     return priv->pipe.empty();
 }
 
-uint32_t RedChannelClient::get_pipe_size()
+uint32_t RedChannelClient::get_pipe_size() const
 {
     return priv->pipe.size();
 }
diff --git a/server/red-channel-client.h b/server/red-channel-client.h
index 4f8c7b0d..9d1e50a0 100644
--- a/server/red-channel-client.h
+++ b/server/red-channel-client.h
@@ -97,8 +97,8 @@ public:
     void pipe_add_type(int pipe_item_type);
     static RedPipeItemPtr new_empty_msg(int msg_type);
     void pipe_add_empty_msg(int msg_type);
-    gboolean pipe_is_empty();
-    uint32_t get_pipe_size();
+    bool pipe_is_empty() const;
+    uint32_t get_pipe_size() const;
     Pipe& get_pipe();
     bool is_mini_header() const;