From 8dd05de4cae8dd5238fd1684653762b31c79dd77 Mon Sep 17 00:00:00 2001
From: rlar <rlar>
Date: Wed, 4 Aug 2010 16:03:23 +0000
Subject: [PATCH] bug fix, segfaults and sickness caused by `plot'

---
 ChangeLog              | 7 +++++++
 src/frontend/control.c | 6 ++++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index e188f808a..4a7c4b1aa 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2010-08-04  Robert Larice
+ * src/frontend/control.c :
+    fix an ancient bug, trampling on freed memory causing segfaults and sickness.
+    getlims() {a function used by plot} does surgery to a wordlist,
+      freeing some words.
+    yet docommand() relied on the wordlist being unmodified.
+
 2010-08-02  Robert Larice
  * src/frontend/hpgl.c ,
  * src/frontend/plotting/plot5.c :
diff --git a/src/frontend/control.c b/src/frontend/control.c
index 424194765..beaa6a066 100644
--- a/src/frontend/control.c
+++ b/src/frontend/control.c
@@ -239,8 +239,10 @@ docommand(wordlist *wlist)
         /* Now fix the pointers and advance wlist. */
     out:        wlist->wl_prev = ee;
         if (nextc) {
-            if (nextc->wl_prev)
-                nextc->wl_prev->wl_next = nextc;
+            for(wl=wlist; wl->wl_next; wl=wl->wl_next)
+                ;
+            wl->wl_next = nextc;
+            nextc->wl_prev = wl;
             wlist = nextc->wl_next;
         }
     } while (nextc && wlist);