This is the name of the default template directory. If you do not supply a resource type when including files, they will be found here. By default this is "./templates", meaning that it will look for the templates directory in the same directory as the executing php script.
此變數是預設樣版路徑的名稱，如果你在包入檔案沒有提供檔案來源的話，則系統 會到此目錄下尋找。此變數的預設值是 "./templates"，代表的意義為執行 php 程式碼的同一 個目錄下的 template 子目錄。
Technical Note: It is not recommended to put this directory under the web server document root.
技術提醒： 不建議將此值設定在網頁伺服器根目錄之下。