materio-base-d7/sites/all/modules/contrib/mail/smtp/smtp.install

<?php

/**
 * @file
 * The installation instructions for the SMTP Authentication Support.
 */

/**
 * Implements hook_install().
 */
 function smtp_install() {
   variable_set('smtp_on', 0);
 }

/**
 * Implements hook_uninstall().
 */
function smtp_uninstall() {
  variable_del('smtp_from');
  variable_del('smtp_fromname');
  variable_del('smtp_host');
  variable_del('smtp_hostbackup');
  variable_del('smtp_on');
  variable_del('smtp_password');
  variable_del('smtp_port');
  variable_del('smtp_protocol');
  variable_del('smtp_test_address');
  variable_del('smtp_username');

  if (variable_get('smtp_library', '') == drupal_get_path('module', 'smtp') . '/smtp.module') {
    variable_del('smtp_library');
  }
}

/**
 * Implements hook_enable().
 */
function smtp_enable() {
  $mail_modes = variable_get('mail_system', array('default-system' => 'DefaultMailSystem'));
  $mail_modes['default-system'] = 'SmtpMailSystem';
  variable_set('mail_system', $mail_modes);
}

/**
 * Implements hook_disable().
 */
function smtp_disable() {
  $mail_modes = variable_get('mail_system');
  $mail_modes['default-system'] = 'DefaultMailSystem';
  variable_set('mail_system', $mail_modes);
}

/**
 * Implements hook_update_N().
 * Upgrade to Drupal 7.x
 */
function smtp_update_7000() {
  if (variable_get('smtp_on', 0) != 0) {
    variable_set('mail_system', array('default-system' => 'SmtpMailSystem'));
  }
}