The FINDK procedure searches the index of an indexed file opened
  for keyed access and locates a specific component.

  Syntax:

     FINDK( file_variable, key-number, key-value[[, match-type]]
           [[, ERROR := error-recovery]] );

  The 'file_variable' is the name of the file variable  associated
  with the file to be searched.

  The 'key-number' is a positive integer expression that indicates
  the key position.

  The 'key-value' is an expression that indicates the  key  to  be
  found.   It  must be assignment compatible with the key field in
  the specified key position.

  The  'match-type'  is   an   identifier   that   indicates   the
  relationship  between  the key value in the FINDK procedure call
  and key value of a component.

  The 'error-recovery' specifies the action  to  be  taken  if  an
  error occurs during execution of the routine.  By default, after
  the first error, the error message is printed and  execution  is
  stopped.

  When you establish key fields with the KEY attribute, you assign
  each  one  a  key number from 0 to 254.  Key number 0 represents
  the mandatory primary key of the  file.   Separate  indexes  are
  built for each key number in the file.

  The key value and the match type provide information  about  the
  key  to  be  found.  The key value must be assignment compatible
  with the key fields of the key number being searched.  The match
  type  must be EQL (equal to the key value), NXT (the next key in
  the collating sequence after the key value), or NXTEQL (the next
  or equal key in the collating sequence after the key value).

  If the FINDK  procedure  was  used  on  an  ascending  collating
  sequence, NXT and NXTEQL would be equivalent to GTR and GEQ.  If
  a descending collating sequence was used, it would be  the  same
  as  LSS  and  LEQ.   The  match type is optional; if omitted, it
  defaults to EQL.

  The FINDK procedure can be called for any  indexed  file  opened
  for  keyed  access,  regardless  of  the  file's  mode.   If the
  component described exists, the file buffer is filled with  that
  component;  UFB  and  EOF both become FALSE.  The mode is set to
  inspection and the component is  automatically  locked.   If  no
  component  is  found  to match the description, UFB becomes TRUE
  and EOF is undefined.  The mode is set to undefined.

  See the "HP  Pascal  Language  Reference  Manual"  for  complete
  information on the FINDK procedure.