is_blog_user( int $blog_id )

Source

File: wp-includes/deprecated.php

function is_blog_user( $blog_id = 0 ) {
	_deprecated_function( __FUNCTION__, '3.3.0', 'is_user_member_of_blog()' );

	return is_user_member_of_blog( get_current_user_id(), $blog_id );
}