POSKEY Subroutine

      SUBROUTINE POSKEY(KULNAM,KLUOUT,HKEYWD1,HKEYWD2)
!!    ################################################
!!
!!*** *POSKEY*
!!
!!    PURPOSE
!!    -------
!     To position namelist file at correct place after reading
!     keyword HKEYWD
!!
!!**  METHOD
!!    ------
!!
!!    EXTERNAL
!!    --------
!!
!!    IMPLICIT ARGUMENT
!!    -----------------
!!
!!    REFERENCE
!!    ----------
!!
!!    AUTHOR
!!    -------
!!       I. Mallet *Meteo-France*
!!
!!    MODIFICATIONS
!!    --------------
!!       Original : 15/10/01
!------------------------------------------------------------------------------
!
IMPLICIT NONE
!
!*       0.    DECLARATIONS
!              ------------
!
!*       0.1   Declarations of arguments
!
INTEGER,                    INTENT(IN) :: KULNAM
INTEGER,                    INTENT(IN) :: KLUOUT
 CHARACTER(LEN=*),           INTENT(IN) :: HKEYWD1
 CHARACTER(LEN=*), OPTIONAL, INTENT(IN) :: HKEYWD2
!
!*       0.2   Declarations of local variables
!
 CHARACTER(LEN=120) :: YLINE
INTEGER            :: ILEN1,ILEN2,IRET
REAL(KIND=JPRB) :: ZHOOK_HANDLE
!
!*       1.    POSITION FILE
!              -------------
!
IF (LHOOK) CALL DR_HOOK('MODE_POS_SURF:POSKEY',0,ZHOOK_HANDLE)
REWIND(KULNAM)
ILEN1=LEN(HKEYWD1)
IF (PRESENT(HKEYWD2)) ILEN2=LEN(HKEYWD2)
!
search_key : DO
      YLINE=' '
      READ(UNIT=KULNAM,FMT='(A)',IOSTAT=IRET,END=100) YLINE
      IF (IRET /=0 ) THEN
         WRITE(KLUOUT,FMT=*) '-> error when reading line from unit ',KULNAM
      ELSE
        YLINE=ADJUSTL(YLINE)
        IF (YLINE(1:ILEN1) .EQ. HKEYWD1(1:ILEN1)) EXIT search_key
      ENDIF
ENDDO search_key
!
WRITE(KLUOUT,FMT=*) '-- keyword ',HKEYWD1,' found'
!
IF (LHOOK) CALL DR_HOOK('MODE_POS_SURF:POSKEY',1,ZHOOK_HANDLE)
RETURN
!
! end of file: keyword not found
100  CONTINUE
IF (.NOT.PRESENT(HKEYWD2)) THEN
  CALL ABOR1_SFX('MODE_POS_SURF: KEYWORD NOT FOUND: '//HKEYWD1)
ELSE
!
!*       2.    SECOND KEYWORD: POSITION FILE
!              -----------------------------
!
  REWIND(KULNAM)
  search_key2 : DO
      YLINE=' '
      READ(UNIT=KULNAM,FMT='(A)',IOSTAT=IRET,END=101) YLINE
      IF (IRET /=0 ) THEN
        WRITE(KLUOUT,FMT=*) '-> error when reading line from unit ',KULNAM
      ELSE
        YLINE=ADJUSTL(YLINE)
        IF (YLINE(1:ILEN2) .EQ. HKEYWD2(1:ILEN2)) EXIT search_key2
      ENDIF
  ENDDO search_key2
  WRITE(KLUOUT,FMT=*) '-- keyword ',HKEYWD2,' found'
  IF (LHOOK) CALL DR_HOOK('MODE_POS_SURF:POSKEY',1,ZHOOK_HANDLE)
  RETURN
END IF
! end of file: scd keyword not found
101  CONTINUE
 CALL ABOR1_SFX('MODE_POS_SURF: KEYWORD NOT FOUND: '//HKEYWD2)
IF (LHOOK) CALL DR_HOOK('MODE_POS_SURF:POSKEY',1,ZHOOK_HANDLE)
!------------------------------------------------------------------
END SUBROUTINE POSKEY