How to call a plug-in function from template

Hello verybody,

I am using version 4.

I write a function, named function.myfunc.php and saved in [font=arial, sans-serif][size=3] /app/functions/smarty_[/size][/font][font=arial, sans-serif][size=3]plugins folder, also to this folder [/size][/font]/app/lib/other/smarty/plugins

[font=arial, sans-serif][size=3]function smarty_function_myfunc($params, &$smarty) {[/size][/font]

[font=arial, sans-serif][size=3]// my function code [/size][/font]

[font=arial, sans-serif][size=3]}[/size][/font]

[font=arial, sans-serif][size=3]And in the template .tpl file, I call this function {myfunc}[/size][/font]

[font=arial, sans-serif][size=3]Then clear the cache (admin.php?cc as well as delete the cache folder) then reload the page but it will return the blank page. Please help me how to call my own function from template file[/size][/font]

[font=arial, sans-serif][size=3]Thank you[/size][/font]