BUG: Check for NULL in PrintSelf

Must check for NULL before printing OutputString.

Change-Id: I7aa92cccc12598e64884a67fb959d3b9cada99c9

Hybrid/vtkX3DExporter.cxx

@@ -623,7 +623,10 @@ void vtkX3DExporter::PrintSelf(ostream& os, vtkIndent indent)
   os << indent << "WriteToOutputString: "
      << (this->WriteToOutputString ? "On" : "Off") << std::endl;
   os << indent << "OutputStringLength: " << this->OutputStringLength << std::endl;
-  os << indent << "OutputString: " << this->OutputString << std::endl;
+  if (this->OutputString)
+    {
+    os << indent << "OutputString: " << this->OutputString << std::endl;
+    }
 }
 
 

Hybrid/vtkX3DExporterWriter.cxx

@@ -41,7 +41,10 @@ void vtkX3DExporterWriter::PrintSelf(ostream& os, vtkIndent indent)
   os << indent << "WriteToOutputString: "
      << (this->WriteToOutputString ? "On" : "Off") << std::endl;
   os << indent << "OutputStringLength: " << this->OutputStringLength << std::endl;
-  os << indent << "OutputString: " << this->OutputString << std::endl;
+  if (this->OutputString)
+    {
+    os << indent << "OutputString: " << this->OutputString << std::endl;
+    }
 }
 
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