The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.
CAL_GREGORIAN 
    (integer)
   CAL_JULIAN 
    (integer)
   CAL_JEWISH 
    (integer)
   CAL_FRENCH 
    (integer)
   CAL_NUM_CALS 
    (integer)
   CAL_DOW_DAYNO 
    (integer)
   CAL_DOW_SHORT 
    (integer)
   CAL_DOW_LONG 
    (integer)
   CAL_MONTH_GREGORIAN_SHORT 
    (integer)
   CAL_MONTH_GREGORIAN_LONG 
    (integer)
   CAL_MONTH_JULIAN_SHORT 
    (integer)
   CAL_MONTH_JULIAN_LONG 
    (integer)
   CAL_MONTH_JEWISH 
    (integer)
   CAL_MONTH_FRENCH 
    (integer)
   The following constants are available since PHP 4.3.0 :
CAL_EASTER_DEFAULT 
    (integer)
   CAL_EASTER_ROMAN 
    (integer)
   CAL_EASTER_ALWAYS_GREGORIAN 
    (integer)
   CAL_EASTER_ALWAYS_JULIAN 
    (integer)
   The following constants are available since PHP 5.0.0 :