Calling watchdog function (logging info) in Drupal 6

In Drupal 6, the way watchdog() is used has changed a bit.

It's all defined in the API, of course, but some things could use a little more clarification.

Here's the function definition as a starting point:
http://api.drupal.org/api/function/watchdog/6

<?php
function watchdog($type, $message, $variables = array(), $severity = WATCHDOG_NOTICE, $link = NULL)
?>

And Agaric's explanation of watchdog's parameters, in we hope something closer to layman's terms:

• $type is typically the module name (the module from which you are calling watchdog).
• $message is your error message. You can use percent-style (and I suppose other) placeholders (%placeholder) but do not wrap your text in the t() function— this function will be called by the various implementations of hook_watchdog.
• $variables is an array holding your placeholders in '%placeholder' => $placeholder syntax.
• $severity is what you might have been thinking for "type." watchdog_severity_levels defines a slew of them, but you will probably most often be using the default WATCHDOG_NOTICE or replacing it with WATCHDOG_ERROR.

See a simple example of watchdog being called in action (er, honestly, no pun intended) in actions_save().

Resolution