8 calls to date_is_valid() in Date 5

date_array2iso in ./date.inc

Date conversion functions

date_array2unix in ./date.inc

date_field in ./date.module

Implementation of hook_field().

date_iso2array in ./date.inc

date_iso2unix in ./date.inc

date_unix2array in ./date.inc

date_unix2iso in ./date.inc

_date_views_filter_handler in ./date_views.inc