FirstDay()

         Returns the first day of the month

    Syntax:

         FirstDay ( dDate ) -> dFirstDay

         dDate : The date which month is going to be treated

    Description:

         Returns the date of the first day at the specified
         Date or month of the system data.

    Return:

         First day of the month Date.

    Example:

         ? FirstDay()                         // 01/03/93
         ? FirstDay( cTod ( "22/01/92" ) )    // 01/01/92