Index Page dafopr_c

A B C D E F G H I J K L M N O P Q R S T U V W X

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

#### Link to routine dafopr_c source file dafopr_c.c

    Wed Apr  5 17:54:31 2017