How can I check if a variable exists in Smarty?

Question

I'm using Smarty template engine.

I'm doing a simple login page. I set a variabile named error with a message if there are some problems, but IF NOT I get:

Notice: Undefined index: error 

How could I check if this variable exists?

I only do:

{if $error}<h1>{$error}</h1>{/if} 

thanks

Answer 1

There you go!

{if isset($error)}     {* TODO something *} {/if}