diff -r caf16813b1e8 -r 1782aa72495a lemon/glpk.h
--- a/lemon/glpk.h	Sat Jul 21 10:18:57 2012 +0200
+++ b/lemon/glpk.h	Fri Jul 20 17:09:01 2012 +0200
@@ -115,6 +115,8 @@
 
     virtual void _messageLevel(MessageLevel level);
 
+    virtual void _write(std::string file, std::string format) const;
+
   private:
 
     static void freeEnv();
@@ -144,6 +146,19 @@
     ///Returns the variable identifier understood by GLPK.
     int lpxCol(Col c) const { return cols(id(c)); }
 
+#ifdef DOXYGEN
+    /// Write the problem or the solution to a file in the given format
+    
+    /// This function writes the problem or the solution
+    /// to a file in the given format.
+    /// Trying to write in an unsupported format will trigger
+    /// \ref UnsupportedFormatError.
+    /// \param file The file path
+    /// \param format The output file format.
+    /// Supportted formats are "MPS" and "LP".
+    void write(std::string file, std::string format = "MPS") const {}
+#endif
+
   };
 
   /// \brief Interface for the GLPK LP solver