===================================================================
RCS file: /home/cvs/OpenXM_contrib2/asir2000/engine/gmpq.c,v
retrieving revision 1.6
retrieving revision 1.7
diff -u -p -r1.6 -r1.7
--- OpenXM_contrib2/asir2000/engine/gmpq.c	2017/02/21 09:20:23	1.6
+++ OpenXM_contrib2/asir2000/engine/gmpq.c	2017/02/28 07:06:28	1.7
@@ -1324,7 +1324,10 @@ void lmtolf(LM a,GZ *b)
 {
   Q q;
 
-  NTOQ(BDY(a),1,q); *b = ztogz(q);
+  if ( !a ) *b = 0;
+  else {
+    NTOQ(BDY(a),1,q); *b = ztogz(q);
+  }
 }
 
 void setmod_lf(N p)