From 27782d7c8b2f8355208ac3ccd7971a02275f9c94 Mon Sep 17 00:00:00 2001
From: Csaba Halasz <Csaba.Halasz@gmail.com>
Date: Sun, 31 Oct 2010 00:36:54 +0200
Subject: [PATCH] Added null pointer check to AI subsystem tear down in
 FGGlobals destructor to avoid crash when using --help option

---
 src/Main/globals.cxx | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/Main/globals.cxx b/src/Main/globals.cxx
index db6eef28c..c28c9f5d2 100644
--- a/src/Main/globals.cxx
+++ b/src/Main/globals.cxx
@@ -167,8 +167,10 @@ FGGlobals::~FGGlobals()
     // shut down all subsystems, make sure we take down the 
     // AIModels system first.
     SGSubsystem* ai = subsystem_mgr->remove("ai_model");
-    ai->unbind();
-    delete ai;
+    if (ai) {
+        ai->unbind();
+        delete ai;
+    }
     
     subsystem_mgr->unbind();
     delete subsystem_mgr;
-- 
2.39.5