is ther a drupal function to jump out of the page rendering process and return a page not found?

I would like to have the choice in a variable_load function (as used to load variables from menu arguments) to circumvent the remainder of the page rendering process and give the user a "page not found."

I could use a drupal_goto() but I would prefer not to redirect the user and change the url in their browser.

Is this possible?

From stackoverflow

• you could use drupal_not_found() to bring up the "page not found" message without altering the URL.