Note: this list is generated by pattern matching, so it may include some functions that are not actually implementations of this hook.

date_field_is_empty in core/modules/date/date.field.inc
Implements hook_field_is_empty().
email_field_is_empty in core/modules/email/email.module
Implements hook_field_is_empty().
entityreference_field_is_empty in core/modules/entityreference/entityreference.module
Implements hook_field_is_empty().
field_example_field_is_empty in modules/examples/field_example/field_example.module
Implements hook_field_is_empty().
field_permission_example_field_is_empty in modules/examples/field_permission_example/field_permission_example.module
Implements hook_field_is_empty().
field_test_field_is_empty in core/modules/field/tests/field_test/field_test.field.inc
Implements hook_field_is_empty().
file_field_is_empty in core/modules/file/file.field.inc
Implements hook_field_is_empty().
image_field_is_empty in core/modules/image/image.field.inc
Implements hook_field_is_empty().
link_field_is_empty in core/modules/link/link.module
Implements hook_field_is_empty().
list_field_is_empty in core/modules/field/modules/list/list.module
Implements hook_field_is_empty().
number_field_is_empty in core/modules/field/modules/number/number.module
Implements hook_field_is_empty().
taxonomy_field_is_empty in core/modules/taxonomy/taxonomy.module
Implements hook_field_is_empty().
text_field_is_empty in core/modules/field/modules/text/text.module
Implements hook_field_is_empty().