add alert message

[flightgear.git] / src / Scripting / NasalSys.cxx

diff --git a/src/Scripting/NasalSys.cxx b/src/Scripting/NasalSys.cxx
index 7e8cba465a6c478e98918d314fe489dd7378c0d2..ae3d51631cb044b2576b4209a990f6d0967e215f 100644 (file)
--- a/src/Scripting/NasalSys.cxx
+++ b/src/Scripting/NasalSys.cxx
@@ -697,6 +697,12 @@ FGNasalModelData::~FGNasalModelData()
         return;
 
     FGNasalSys *nas = (FGNasalSys *)globals->get_subsystem("nasal");
+    if (!nas) {
+        SG_LOG(SG_NASAL, SG_ALERT, "Trying to run an <unload> script "
+                "without Nasal subsystem present.");
+        return;
+    }
+
     if (_unload) {
         const char *s = _unload->getStringValue();
         nas->createModule(_module.c_str(), _module.c_str(), s, strlen(s));