| aggregator_categorize_items_validate | modules/aggregator/aggregator.pages.inc | Validate aggregator_categorize_items form submissions. |
| date_validate | includes/form.inc | Validates the date type to stop dates like February 30, 2006. |
| example_element_phonenumber_validate | developer/examples/example_element.module | Our element's validation function. |
| form_error | includes/form.inc | Flag an element as having an error. |
| install_configure_form_validate | install.php | Form API validate for the site configuration form. |
| password_confirm_validate | includes/form.inc | Validate password_confirm element. |
| _form_validate | includes/form.inc | Performs validation on form elements. First ensures required fields are
completed, #maxlength is not exceeded, and selected options were in the
list of options given to the user. Then calls user-defined validators. |
