--- a/src/file-io.cc
+++ b/src/file-io.cc
@@ -1184,17 +1184,24 @@
 
       if (! error_state)
 	{
-	  octave_value size = (nargin > 1)
-	    ? args(1) : octave_value (lo_ieee_inf_value ());
+	  octave_value size = lo_ieee_inf_value ();
+	  octave_value prec = "uchar";
+	  octave_value skip = 0;
+	  octave_value arch = "unknown";
 
-	  octave_value prec = (nargin > 2)
-	    ? args(2) : octave_value ("uchar");
+	  int idx = 1;
 
-	  octave_value skip = (nargin > 3)
-	    ? args(3) : octave_value (0.0);
+	  if (nargin > 1 && ! args(idx).is_string ())
+	    size = args(idx++);
+
+	  if (nargin > idx)
+	    prec = args(idx++);
 
-	  octave_value arch = (nargin > 4)
-	    ? args(4) : octave_value ("unknown");
+	  if (nargin > idx)
+	    skip = args(idx++);
+
+	  if (nargin > idx)
+	    arch = args(idx++);
 
 	  int count = -1;