Template:Missing param
Documentation
This template provides a simple way to specify an error message to be shown when a template that requires some specific input is called without it. The template displays an error message in red and places the page containing the offending template call into Category:Template calls needing input (unless that categorization is suppressed — see below). No mechanism is provided for avoiding broken links and other kinds of invalid wiki markup caused by the error message itself, which is partly why it's so prominent. It is hoped that such errors will be noticed and fixed by editors when previewing changes before the page is saved.
This template should not be used directly in articles, only in other templates.
Usage
{{missing param|parameter description}}{{missing param|parameter description|template=Template name}}{{missing param|…|nocat=y}}{{missing param|…|nocat={{{nocat|}}}}}
When the template name is provided, the error message will include a link to the documentaton of the called template (see examples below).
The optional parameter nocat is most useful when illustrating bad template calls on template documentation subpages. In that case, nocat={{{nocat|}}} would be used in the call to {{missing param}} inside the template that is being documented, while nocat=y would be used in the example on the template documentation subpage. This prevents the intentional errors shown in template documentation from being tracked in Category:Template calls needing input while still allowing actual mistakes in articles to be tracked.
Examples
{{missing param}}⇒ please provide missing information{{missing param|URL}}⇒ please provide URL{{missing param|video ID|template=Ytv-thumb}}⇒ please provide video ID—see documentation
