diff --git a/src/Clp_C_Interface.h b/src/Clp_C_Interface.h
index 567a8e28..005401db 100644
--- a/src/Clp_C_Interface.h
+++ b/src/Clp_C_Interface.h
@@ -18,8 +18,18 @@
 #define CLP_LINKAGE_CB
 #endif
 
+/** User does not need to see structure of model but C++ code does */
+#if defined(CLP_EXTERN_C)
+/* Real typedef for structure */
+class CMessageHandler;
+typedef struct {
+  ClpSimplex *model_;
+  CMessageHandler *handler_;
+} Clp_Simplex;
+#else
 struct Clp_Simplex_s;
 typedef struct Clp_Simplex_s Clp_Simplex;
+#endif
 
 struct Clp_Solve_s;
 typedef struct Clp_Solve_s Clp_Solve;