I tried copying the functions from the field module in [example modules][1] to get a field to show up in Manage Fields without necessarily any functionality

Looking at the answer to this question, only field_create_field() and hook_field_info() should do the trick but I never got that working with the following code: 

 function entityreference_add_new_field_info() {
 return array(
 'entityreference_add_link' => array(
 'label' => t('Entityreference link'),
 'description' => t('Entityreference link'),
 'default_widget' => 'entityreference_link_widget',
 'default_formatter' => 'entityreference_link_formatter',
 ),
 ); 
 field_create_field('entityreference_add_link');
 }

Putting `field_create_field()` outside of `hook_field_info()` returns 'call to undefined function' error. 


**Update:** Here's one thing I've tried without success: 

 function entityreference_add_new_field_info() {
 return array(
 'entityreference_add_link' => array(
 'label' => t('Entityreference link'),
 'description' => t('Entityreference link'),
 'default_widget' => 'entityreference_link_widget',
 'default_formatter' => 'entityreference_link_formatter',
 ),
 ); 
 field_create_field('entityreference_add_link');
 
 
 $instance = array(
 'field_name' => 'entityrefernce_add_link',
 'entity_type' => 'node', 
 'label' => 'The Link', 
 'bundle' => 'node', 
 );
 
 field_create_instance($instance);
 
 }
 enter code here

 [1]: http://drupal.org/project/examples