Drupal form textfield required syntax

Drupal form textfield FAQ: What is the syntax to make a Drupal textfield required?

Just use the Drupal form #required property, like this:

$form['first_name'] = array(
  '#title' => t('First Name'),
  '#type' => 'textfield',
  '#required' => TRUE,
);

In that example the Drupal form textfield is made required by setting the "#required" tag equal to TRUE.