How to use hook_user_login and hook_user_logout to output content to the page

Question

I came across this post: execute a php code after a user login and I implemented the accepted solution. In my implementation, however, I'm trying to output content to the page. This simply doesn't show up. My module name is "alert", and here's the code:

alert.module

<?php

function alert_user_login(&$edit, $account) {
  for ($i=0; $i < 1000; $i++) { 
    echo 'hi<br>';
  }
}

alert.install

<?php

function alert_install() {
  // Set the module weight so it can override other modules.
  db_query("UPDATE {system} SET weight = 99 WHERE name = 'alert'");
}

function alert_uninstall() {
  // Remove the module from the system table
  db_query("DELETE FROM {system} WHERE name = 'alert'");
}

alert.info

; $Id$
name = Alert
description = Present dialogs or perform redirects based on certain events
core = 7.x

I'm implementing this in my theme's template.php file. Should this work?

Answer 1

It will not work in template.php You need to add this in a module file, check here on howto instead of myTheme it will be modulename If module name is foo then it will be foo_user_login

    // @file : foo.module
    function foo_user_login(&$edit, $account) {
      fluenz_user_function($account->uid);
    }
    // and this function name was also different just an FYI
    function fluenz_user_function($uid) {
      for ($i=0; $i < 1000; $i++) { 
        echo 'hi<br>';
      }
    }

Answer 2

hook_user_login(), and hook_user_logout() are not thought to be used to alter the content of a page. They are thought to record the fact a user logged in, or logged out, and eventually set a message with drupal_set_message(). To notice that the answer for the question you are referring is talking of executing code, not printing a string through print(), or echo().

hook_user_login() could be used to set a global variable, or a static variable (see drupal_static()) that is retrieved from another hook.

For altering the content of a page, there are other hooks; which one you should use depends from what exactly you want to achieve.