diff --git a/gio/src/memoryoutputstream.hg b/gio/src/memoryoutputstream.hg
index cf6276e..7f092e9 100644
--- a/gio/src/memoryoutputstream.hg
+++ b/gio/src/memoryoutputstream.hg
@@ -45,11 +45,11 @@ class MemoryOutputStream :
   _IMPLEMENTS_INTERFACE(Seekable)
 protected:
   // TODO: more C++-like interface using sigc++
-  _WRAP_CTOR(MemoryOutputStream(gpointer data, gsize len, GReallocFunc realloc_fn, GDestroyNotify destroy), g_memory_output_stream_new)
+  _WRAP_CTOR(MemoryOutputStream(gpointer data, gsize size, GReallocFunc realloc_function, GDestroyNotify destroy_function), g_memory_output_stream_new)
 
 public:
   // TODO: more C++-like interface using sigc++
-  _WRAP_CREATE(gpointer data, gsize len, GReallocFunc realloc_fn, GDestroyNotify destroy)
+  _WRAP_CREATE(gpointer data, gsize size, GReallocFunc realloc_function, GDestroyNotify destroy_function)
   _WRAP_METHOD(gpointer get_data(), g_memory_output_stream_get_data)
   _WRAP_METHOD(gsize get_size() const, g_memory_output_stream_get_size)
   _WRAP_METHOD(gsize get_data_size() const, g_memory_output_stream_get_data_size)
