--- a/src/pt-plot.cc	Fri Sep 23 12:53:05 1994 +0000
+++ b/src/pt-plot.cc	Sat Sep 24 03:22:34 1994 +0000
@@ -59,13 +59,13 @@
 }
 
 // The number of lines we\'ve plotted so far.
-int plot_line_count = 0;
+static int plot_line_count = 0;
 
 // Is this a parametric plot?  Makes a difference for 3D plotting.
-int parametric_plot = 0;
+static int parametric_plot = 0;
 
 // Should the graph window be cleared before plotting the next line?
-int clear_before_plotting = 1;
+static int clear_before_plotting = 1;
 
 // List of files to delete when we exit or crash.
 static SLStack <char *> tmp_files;
@@ -902,6 +902,14 @@
   return retval;
 }
 
+DEFUN ("ishold", Fishold, Sishold, 0, 1,
+  "ishold\n\
+\n\
+Return 1 if hold is on, otherwise return 0.")
+{
+  return (double) (! clear_before_plotting);
+}
+
 DEFUN ("purge_tmp_files", Fpurge_tmp_files, Spurge_tmp_files, 5, 1,
   "delete temporary data files used for plotting")
 {