# File lib/phusion_passenger/ruby_core_enhancements.rb, line 43
        def backtrace_string(current_location = nil)
                if current_location.nil?
                        location = nil
                else
                        location = "in #{current_location} "
                end
                current_thread = Thread.current
                if !(thread_id = current_thread[:id])
                        current_thread.to_s =~ /:(0x[0-9a-f]+)/i
                        thread_id = $1 || '?'
                end
                if thread_name = current_thread[:name]
                        thread_name = "(#{thread_name})"
                end
                return "*** Exception #{self.class} #{location}" <<
                        "(#{self}) (process #{$$}, thread #{thread_id}#{thread_name}):\n" <<
                        "\tfrom " << backtrace.join("\n\tfrom ")
        end