Rik Wasmus wrote:

> What are the 'filter functions' you're talking about?
>
filter_has_var()
filter_id()
filter_input_array()
filter_input()
filter_list()
filter_var_array()
filter_var()

But I now realize they are part of an installable extension, not core
PHP. So the point may be moot, since I no longer run my own servers
(and thus can't control extension installation)

> Besides that, validating is often just using the right tool for the job.
> Is it a number, is a record in a database that should exist etc... All
> depending on the desired implementation.

.... and preventing unwanted or hazardous input, and so on, so I asked
about two of the many tools I see in PHP.