diff -r cd72eae05bdf -r 3c00344f49c9 lemon/lp_skeleton.cc
--- a/lemon/lp_skeleton.cc	Mon Jul 16 16:21:40 2018 +0200
+++ b/lemon/lp_skeleton.cc	Wed Oct 17 19:14:07 2018 +0200
@@ -2,7 +2,7 @@
  *
  * This file is a part of LEMON, a generic C++ optimization library.
  *
- * Copyright (C) 2003-2010
+ * Copyright (C) 2003-2013
  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
  * (Egervary Research Group on Combinatorial Optimization, EGRES).
  *
@@ -91,6 +91,8 @@
 
   void SkeletonSolverBase::_messageLevel(MessageLevel) {}
 
+  void SkeletonSolverBase::_write(std::string, std::string) const {}
+
   LpSkeleton::SolveExitStatus LpSkeleton::_solve() { return SOLVED; }
 
   LpSkeleton::Value LpSkeleton::_getPrimal(int) const { return 0; }