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dafopr_c
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Procedure
Abstract
Required_Reading
Keywords
Brief_I/O
Detailed_Input
Detailed_Output
Parameters
Exceptions
Files
Particulars
Examples
Restrictions
Literature_References
Author_and_Institution
Version
Index_Entries

Procedure

   void dafopr_c ( ConstSpiceChar    * fname,
                   SpiceInt          * handle  )

Abstract

   Open a DAF for subsequent read requests.

Required_Reading

   DAF

Keywords

   DAF
   FILES


Brief_I/O

   Variable  I/O  Description
   --------  ---  --------------------------------------------------
   fname      I   Name of DAF to be opened.
   handle     O   Handle assigned to DAF.

Detailed_Input

   fname       is the file name of a DAF to be opened for read
               access.

Detailed_Output

   handle      is the file handle associated with the file. This
               handle is used to identify the file in subsequent
               calls to other DAF routines.

Parameters

  None.

Exceptions

   1) If the specified file has already been opened for read
      access, the handle already associated with the file is
      returned.

   2) If the specified file has already been opened for write
      access, the error SPICE(DAFRWCONFLICT) is signaled.

   3) If the specified file has already been opened by a non-DAF
      routine, the error SPICE(DAFIMPROPOPEN) is signaled.

   4) If the specified file cannot be opened without exceeding
      the maximum number of files, the error SPICE(DAFFTFULL)
      is signaled.

   5) If (for some reason) the file cannot be opened properly,
      the error SPICE(DAFOPENFAIL) is signaled.

   6) If the attempt to read the file's ID word fails, the error
      SPICE(FILEREADFAILED) will be signaled.

   7) If the specified file is not a DAF file, as indicated by the
      file's ID word, the error SPICE(NOTADAFFILE) is signaled.

   8) If no logical units are available, the error will be
      signaled by routines called by this routine.

   9) If the file does not exist, the error SPICE(FILEDOESNOTEXIST)
      is signaled.

  10) If the INQUIRE fails, the error SPICE(INQUIREFAILED)
      is signaled.

  11) If the file record cannot (for some reason) be read,
      the error SPICE(DAFFRNOTFOUND) is signaled.

  12) If the file name is blank, the error SPICE(BLANKFILENAME)
      is signaled.

Files

   See argument fname.

Particulars

   Most DAFs require only read access. If you do not need to
   change the contents of a file, you should open it with dafopr_c.

Examples

   Example (1):

   In the following code fragment, dafopr_c is used to open a file,
   which is then searched for DAFs containing data for a particular
   object.

      #include "SpiceUsr.h"
           .
           .
           .
      dafopr_c ( fname, &handle );
      dafbfs_c ( handle );

      daffna_c ( &found );

      while ( found )
      {
         dafgs_c ( sum );
         dafus_c ( sum, ND, NI, dc, ic );

         if ( ic[0] == target_object )
         {
            .
            .
            .
         }

         daffna_c ( &found );
      }

   Example (2):

   Use a simple routine to output the double precision and integer
   values stored in an SPK's segments descriptors. This function
   opens a DAF for read, performs a forwards search for the DAF
   arrays, prints segments description for each array found, then
   closes the DAF.

      #include <stdio.h>
      #include "SpiceUsr.h"

      int main()
         {

         /.
         Local constants
         ./

         /.
         Define the summary parameters appropriate
         for an SPK file.
         ./

         #define ND              2
         #define NI              6
         #define MAXSUM          125

         SpiceInt                ic  [ NI ];
         SpiceInt                handle;

         SpiceDouble             dc  [ ND ];
         SpiceDouble             sum [ MAXSUM ];

         SpiceChar             * kernel = "de421.bsp";

         SpiceBoolean            found;


         /.
         Open a DAF for read. Return a handle referring to the file.
         ./
         dafopr_c ( kernel, &handle );

         /.
         Begin a forward search on the file.
         ./
         dafbfs_c ( handle );

         /.
         Search until a DAF array is found.
         ./
         daffna_c ( &found );

         /.
         Loop while the search finds subsequent DAF arrays.
         ./
         while ( found )
            {

            dafgs_c ( sum );
            dafus_c ( sum, ND, NI, dc, ic );

            printf( " Doubles: %f %f \n", dc[0], dc[1] );
            printf( "Integers: %d %d %d %d %d %d\n\n",
                       (int)ic[0], (int)ic[1], (int)ic[2],
                       (int)ic[3], (int)ic[4], (int)ic[5] );


            /.
            Check for another segment.
            ./
            daffna_c ( &found );
            }

         /.
         Safely close the DAF.
         ./
         dafcls_c ( handle  );

         return ( 0 );
         }

   The program outputs:

       Doubles: -3169195200.000000 1696852800.000000 
      Integers: 1 0 1 2 641 310404
      
       Doubles: -3169195200.000000 1696852800.000000 
      Integers: 2 0 1 2 310405 423048
      
       Doubles: -3169195200.000000 1696852800.000000 
      Integers: 3 0 1 2 423049 567372
      
       Doubles: -3169195200.000000 1696852800.000000 
      Integers: 4 0 1 2 567373 628976
      
       Doubles: -3169195200.000000 1696852800.000000 
      Integers: 5 0 1 2 628977 674740
      
       Doubles: -3169195200.000000 1696852800.000000 
      Integers: 6 0 1 2 674741 715224
      
       Doubles: -3169195200.000000 1696852800.000000 
      Integers: 7 0 1 2 715225 750428
      
       Doubles: -3169195200.000000 1696852800.000000 
      Integers: 8 0 1 2 750429 785632
      
       Doubles: -3169195200.000000 1696852800.000000 
      Integers: 9 0 1 2 785633 820836
      
       Doubles: -3169195200.000000 1696852800.000000 
      Integers: 10 0 1 2 820837 944040
      
       Doubles: -3169195200.000000 1696852800.000000 
      Integers: 301 3 1 2 944041 1521324
      
       Doubles: -3169195200.000000 1696852800.000000 
      Integers: 399 3 1 2 1521325 2098608
      
       Doubles: -3169195200.000000 1696852800.000000 
      Integers: 199 1 1 2 2098609 2098620
      
       Doubles: -3169195200.000000 1696852800.000000 
      Integers: 299 2 1 2 2098621 2098632
      
       Doubles: -3169195200.000000 1696852800.000000 
      Integers: 499 4 1 2 2098633 2098644

      Note, the final entries in the integer array contains the segment
      start/end indexes. The output indicates the search proceeded
      from the start of the file (low value index) towards the end
      (high value index).

Restrictions

   None.

Literature_References

   None.

Author_and_Institution

   N.J. Bachman    (JPL)
   K.R. Gehringer  (JPL)
   J.M. Lynch      (JPL)
   W.L. Taber      (JPL)
   I.M. Underwood  (JPL)

Version

   -CSPICE Version 1.0.2, 28-JUN-2016 (EDW)

      Edit to Example code, SpiceInts output as ints using 
      explicit casting.

   -CSPICE Version 1.0.1, 10-OCT-2012 (EDW)

      Added a functional code example to the Examples section.

      Removed the obsolete Reference citation to "NAIF
      Document 167.0."

   -CSPICE Version 1.0.0, 01-AUG-1999 (NJB) (KRG) (JML) (WLT) (IMU)

Index_Entries

   open daf for read
Wed Apr  5 17:54:31 2017