From: Ben Pfaff <blp@gnu.org>
Date: Mon, 20 Jul 2009 00:11:46 +0000 (-0700)
Subject: charts: Allow passing a null pointer to chart_unref.
X-Git-Tag: v0.7.3~7
X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5278a229f3fce7a8d1f2d8f6b576d1c8b76f3779;p=pspp-builds.git

charts: Allow passing a null pointer to chart_unref.
---

diff --git a/src/output/chart.c b/src/output/chart.c
index b096a7d2..b1f96ef9 100644
--- a/src/output/chart.c
+++ b/src/output/chart.c
@@ -114,9 +114,12 @@ chart_ref (const struct chart *chart_)
 void
 chart_unref (struct chart *chart)
 {
-  assert (chart->ref_cnt > 0);
-  if (--chart->ref_cnt == 0)
-    chart->class->destroy (chart);
+  if (chart != NULL)
+    {
+      assert (chart->ref_cnt > 0);
+      if (--chart->ref_cnt == 0)
+        chart->class->destroy (chart);
+    }
 }
 
 void