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Function Reference/validate username

Checks whether username is valid.

<?php validate_username( $username ) ?>

$username

(string) (required) Username.

Default: None

(boolean): Returns true if $username is valid, false if $username is invalid.

<?php
if (validate_username( $_POST['username'] )) {
  // Go ahead and save the user...
}
?>

Uses: apply_filters() Calls validate_username hook on $valid check and $username as parameters.
Uses: sanitize_user()

Since: 2.0.1

Before 3.0
validate_username() is located in wp-includes/registration.php.

After 3.0
validate_username() is located in wp-includes/user.php.