Procedure

     SGFREF ( Generic Segments: Fetch references )

     SUBROUTINE SGFREF ( HANDLE, DESCR, FIRST, LAST, VALUES )

Abstract

     Fetch from the references partition of a generic segment 
     the double precision numbers from FIRST to LAST. The 
     segment is identified by a DAF file handle and segment 
     descriptor.

Required_Reading

     DAF

Keywords

     GENERIC SEGMENTS

Declarations

     IMPLICIT NONE

     INTEGER               HANDLE
     DOUBLE PRECISION      DESCR  ( * )
     INTEGER               FIRST
     INTEGER               LAST
     DOUBLE PRECISION      VALUES ( * )

Brief_I/O

     VARIABLE  I/O  DESCRIPTION
     --------  ---  --------------------------------------------------
     HANDLE     I   Handle of a DAF open for reading.
     DESCR      I   Descriptor for a generic segment in the DAF.
     FIRST      I   The index of the first reference value to fetch.
     LAST       I   The index of the last reference value to fetch.
     VALUES     O   The reference values that were requested.

Detailed_Input

     HANDLE   is the handle of a DAF file opened for reading
              that contains the segment described by DESCR.

     DESCR    is the descriptor of the segment with the desired
              constant values. This must be the descriptor for a
              segment in the DAF associated with HANDLE.

     FIRST    is the index of the first value to fetch from the
              reference section of the DAF generic segment associated
              with HANDLE and DESCR.

     LAST     is the index of the last value to fetch from the
              constants section of the DAF generic segment associated
              with HANDLE and DESCR.

Detailed_Output

     VALUES   is the array of reference values obtained from the
              reference section of the DAF generic segment
              associated with HANDLE and DESCR.

Parameters

     This subroutine makes use of parameters defined in the file
     'sgparam.inc'.

Exceptions

     1)  If FIRST is less than 1 or LAST is greater than the number of
         reference values, the error SPICE(REQUESTOUTOFBOUNDS) is
         signaled.

     2)  If LAST is less than FIRST, the error SPICE(REQUESTOUTOFORDER)
         is signaled.

     3)  If the reference directory structure is unrecognized, the
         error SPICE(UNKNOWNREFDIR) is signaled. The most likely cause
         of this error is that an upgrade to your version of the SPICE
         toolkit is needed.

Files

     See the description of HANDLE above.

Particulars

     This routine allows you to easily fetch values from the reference
     section of a generic segment.

Examples

     Suppose that you have located a DAF generic segment. The code
     fragment below shows how to fetch the I'th reference value from
     that segment.

        Declarations:

        DOUBLE PRECISION      REFVAL

        Fetch the Ith reference value from the segment.

        CALL SGFREF ( HANDLE, DESCR, I, I, REFVAL )

Restrictions

     1)  The segment described by DESCR MUST be a generic segment,
         otherwise the results of this routine are not predictable.

Literature_References

     None.

Author_and_Institution

     J. Diaz del Rio    (ODC Space)
     K.R. Gehringer     (JPL)
     W.L. Taber         (JPL)
     E.D. Wright        (JPL)

Version

    SPICELIB Version 1.2.1, 26-OCT-2021 (JDR)

        Edited the header to comply with NAIF standard.

    SPICELIB Version 1.2.0, 07-SEP-2001 (EDW)

        Replaced DAFRDA call with DAFGDA.

    SPICELIB Version 1.0.0, 12-APR-1995 (KRG) (WLT)