[support] getting the underscore to be unusable in user names

[Earl Miles]

Neil: esl-lounge.com wrote:
> I have run into trouble with the underscore. (concerning a mesh up 
> between drupal and mediawiki)
>  
> I would like to find a way of getting the underscore on the "banned 
> list" for drupal registrations. If I try and register a name such as 
> "great!!!", I get a message saying:
>  
> "punctuation is not allowed except for periods, hyphens and underscores"
>  
> I would like to make it impossible for underscores. Is this just a case 
> of altering something in user.module?
>  
> many thanks in advance
>  
> Neil
> 

Look up hook_user on api.drupal.org

Write a small module that implements the 'validate' operation.

That way you can make your validation and not have to hack the code.