[development] module_preprocess_hook not always called

[Charlie Gordon]

Template preprocess functions are, as the name implies, only for templates.

-Charlie

Matt Connolly wrote:
> My theme has a theme_links function which generates the html output, 
> but in this case the preprocess function is NOT called.
>
> For other pieces of themed output, using hook.tpl.php files, the 
> preprocess functions ARE called.