# HG changeset patch
# User Andreas Weber <andy.weber.aw@gmail.com>
# Date 1420166856 28800
# Node ID 8dbd557421124a6d67ab3ede6428541e6c2aacaf
# Parent  93dd3457eef93356aea23b196986d56af14d2595
Prevent segfault when video card has insufficient OpenGL support (bug #41747).

* __init_fltk__.cc: Check canvas->can_do () before trying to display plot.

diff --git a/libinterp/dldfcn/__init_fltk__.cc b/libinterp/dldfcn/__init_fltk__.cc
--- a/libinterp/dldfcn/__init_fltk__.cc
+++ b/libinterp/dldfcn/__init_fltk__.cc
@@ -929,7 +929,9 @@
 
   void show_canvas (void)
   {
-    if (fp.is_visible ())
+    if (! canvas->can_do ())
+      error ("unable to plot due to insufficient OpenGL support");
+    else if (fp.is_visible ())
       {
         canvas->show ();
         canvas->make_current ();