wpmu_signup_user_notification filter is used in a boolean — or true/false — capacity to determine whether a confirmation email should be sent for new user signups in Multisite. It defaults to
The filter accepts four arguments:
$userThe user’s login name
$user_emailThe user’s email
$keyThe activation key from
$metaBy default, an empty array
$user is not empty, the filter returns a value of
true. Core uses the filter in just this capacity to disable sending a signup email when the ‘Skip Confirmation Email’ checkbox is selected on the Users > Add New screen.
Let’s say we only want to disable the user confirmation email for users who don’t have a Gmail address. We’ll test the user email for signs of Gmail and return false if we find it.