--- a/liboctave/CmplxSCHUR.cc
+++ b/liboctave/CmplxSCHUR.cc
@@ -70,20 +70,21 @@
       return -1;
     }
 
-  char *jobvs = "V";
-  char *sense = "N";
-  char *sort = "N";
+  char jobvs = 'V';
+  char sense = 'N';
+  char sort = 'N';
 
   char ord_char = ord.empty () ? 'U' : ord[0];
 
   if (ord_char == 'A' || ord_char == 'D' || ord_char == 'a' || ord_char == 'd')
-    sort = "S";
+    sort = 'S';
 
-  select_function selector= 0;
   if (ord_char == 'A' || ord_char == 'a')
     selector = select_ana;
   else if (ord_char == 'D' || ord_char == 'd')
     selector = select_dig;
+  else
+    selector = 0;
 
   int n = a_nc;
   int lwork = 8 * n;
@@ -116,7 +117,7 @@
 
   int *pbwork = bwork.fortran_vec ();
 
-  F77_XFCN (zgeesx, ZGEESX, (jobvs, sort, selector, sense, n, s, n,
+  F77_XFCN (zgeesx, ZGEESX, (&jobvs, &sort, selector, &sense, n, s, n,
 			     sdim, pw, q, n, rconde, rcondv, pwork,
 			     lwork, prwork, pbwork, info, 1L, 1L));