Procedure

   ekopr_c ( EK, open file for reading ) 

   void ekopr_c ( ConstSpiceChar  * fname,
                  SpiceInt        * handle )

Abstract

   Open an existing E-kernel file for reading.

Required_Reading

   EK

Keywords

   EK
   FILES
   UTILITY

Brief_I/O

   VARIABLE  I/O  DESCRIPTION
   --------  ---  --------------------------------------------------
   fname      I   Name of EK file.
   handle     O   Handle attached to EK file.

Detailed_Input

   fname       is the name of an existing E-kernel file to be
               opened for read access.

Detailed_Output

   handle      is the EK file handle of the file designated by
               `fname'. This handle is used to identify the file
               to other EK routines.

Parameters

   SPICE_DAS_FTSIZE

               is the maximum number of DAS files that a user can
               have open simultaneously. This includes any files used
               by the DAS system.

               See the header file SpiceDAS.h for the actual value of
               this parameter.

Exceptions

   1)  If the indicated file cannot be opened, an error is signaled
       by a routine in the call tree of this routine.

   2)  If the indicated file has the wrong architecture version, an
       error is signaled by a routine in the call tree of this
       routine.

   3)  If an I/O error occurs while reading the indicated file, the
       error is signaled by a routine in the call tree of this
       routine.

   4)  If the `fname' input string pointer is null, the error
       SPICE(NULLPOINTER) is signaled.

   5)  If the `fname' input string has zero length, the error
       SPICE(EMPTYSTRING) is signaled.

Files

   See the EK Required Reading for a discussion of the EK file
   format.

Particulars

   This routine should be used to open an EK file for read access.
   EKs opened for read access may not be modified.

   Opening an EK file with this routine makes the EK accessible to
   the CSPICE EK readers

      ekrcec_c
      ekrced_c
      ekrcei_c

   all of which expect an EK file handle as an input argument. These
   readers allow a caller to read individual EK column entries.

   To make an EK available to the EK query system, the file must be
   loaded via eklef_c, rather than by this routine. See the EK
   Required Reading for further information.

Examples

   The numerical results shown for this example may differ across
   platforms. The results depend on the SPICE kernels used as
   input, the compiler and supporting libraries, and the machine
   specific arithmetic implementation.

   1) Open an EK for read access and find the number of segments in
      it.

      Use the EK kernel below as test input file for loading the
      experiment database. This kernel contains the Deep
      Impact spacecraft sequence data based on the integrated
      Predicted Events File covering the whole primary mission,
      split into two segments.

         dif_seq_050112_050729.bes


      Example code begins here.


      /.
         Program ekopr_ex1
      ./
      #include <stdio.h>
      #include "SpiceUsr.h"

      int main( )
      {

         /.
         Local variables.
         ./
         SpiceInt             handle;
         SpiceInt             nseg;

         /.
         Open the EK file, returning the file handle
         associated with the open file to the variable named
         `handle'.
         ./
         ekopr_c ( "dif_seq_050112_050729.bes", &handle );

         /.
         Return the number of segments in the EK.
         ./
         nseg = eknseg_c ( handle );
         printf( "Number of segments = %2d\n", nseg );

         /.
         Close the file.
         ./
         ekcls_c ( handle );

         return ( 0 );
      }


      When this program was executed on a Mac/Intel/cc/64-bit
      platform, the output was:


      Number of segments =  2

Restrictions

   1)  No more than SPICE_DAS_FTSIZE DAS files may be opened simultaneously.
       See the header file SpiceDAS.h for the value of SPICE_DAS_FTSIZE.

Literature_References

   None.

Author_and_Institution

   N.J. Bachman        (JPL)
   J. Diaz del Rio     (ODC Space)

Version

   -CSPICE Version 1.1.1, 10-AUG-2021 (NJB) (JDR)

       Edited the header to comply with NAIF standard. Added complete
       code example.

       Updated the -Exceptions section to correct exception #1 (this
       routine does not delete the input file if the file cannot be opened);
       and add exceptions #4 and #5.

       Added SPICE_DAS_FTSIZE parameter description.

   -CSPICE Version 1.1.0, 23-JUL-2001 (NJB)

       Removed tab characters from source file.

   -CSPICE Version 1.0.0, 27-MAR-1998 (NJB)

Index_Entries

   open EK for reading

Link to routine ekopr_c source file ekopr_c.c