calling mutiple callback function while form validation

[eluser]pallavi312[/eluser]
Hello,

i have one query. my form contains "First Name " field. its mandatory.field should check validation for "shouldn't start with special charcter" & "not end with specail character"
i have function for these two above .
my qs is how to called these two functions while doing validation for "first name" field?

Please reply earlier .. its urgent..

[eluser]verynewtothis[/eluser]
Though I don't understand a need to have 2 separate callback functions for this but the rules are simple, just separate each of them with the pipe characters "|"...
like this:

Code:

$this->form_validation->set_rules('username', 'Username', 'required|callback_username_checkstart|callback_username_checkend');