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KARVFY

       INTEGER FUNCTION KARVFY (TEXT,LOCTXT,LENTXT,
      #                         PATERN,LOCPAT,LENPAT)

          Search the string defined by TEXT,LOCTXT,LENTXT for
 the  first character which  is NOT contained  in the pattern
 string  defined by PATERN,LOCPAT,LENPAT.  If  any of LOCTXT,
 LENTXT, LOCPAT, or LENPAT is  less than 1, return 0.  If all
 characters  in the  first  string  are found  in  PATERN(*),
 return   0.   Otherwise  return  the   index  of  the  first
 mismatching  character in  TEXT(*), counting  from the first
 character  stored in TEXT(*).  Thus  KARVFY always returns a
 value 0,  or  one  which is  not  less  than LOCTXT.  It  is
 important to  note that  the index  returned points  to  the
 first string, not to the pattern string.

          KARVFY is based  upon the PL/1 VERIFY function.  In
 PASCAL, its  would be implemented by  testing a character to
 see if  it belongs  to  the set  of characters  forming  the
 pattern.  For  example, if  the pattern  contained  letters,
 digits, and  a space, then KARVFY would  return the index of
 the first  character  in TEXT(*)  which  was not  a  letter,
 digit,  or space.  This  is a rather  convenient function to
 have for implementing command parsers.