ekrced_c

Index Page ekrced_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 ekrced_c ( SpiceInt           handle,
                       SpiceInt           segno,
                       SpiceInt           recno,
                       ConstSpiceChar   * column,
                       SpiceInt         * nvals,
                       SpiceDouble      * dvals,
                       SpiceBoolean     * isnull )
#### Abstract
       Read data from a double precision column in a specified EK
       record.
#### Required_Reading
       EK
#### Keywords
       EK
       FILES
       UTILITY
#### Brief_I/O
       Variable  I/O  Description
       --------  ---  --------------------------------------------------
       handle     I   Handle attached to EK file.
       segno      I   Index of segment containing record.
       recno      I   Record from which data is to be read.
       column     I   Column name.
       nvals      O   Number of values in column entry.
       dvals      O   D.p. values in column entry.
       isnull     O   Flag indicating whether column entry is null.
#### Detailed_Input
       handle         is an EK file handle.  The file may be open for
                      read or write access.

       segno          is the index of the segment from which data is to
                      be read.  The first segment in the file has index 0.

       recno          is the index of the record from which data is to be
                      read.  This record number is relative to the start
                      of the segment indicated by segno; the first
                      record in the segment has index 0.

       column         is the name of the column from which data is to be
                      read.
#### Detailed_Output
       nvals,
       ivals          are, respectively, the number of values found in
                      the specified column entry and the set of values
                      themselves.

                      For columns having fixed-size entries, when a
                      a column entry is null, nvals is still set to the
                      column entry size.  For columns having variable-
                      size entries, nvals is set to 1 for null entries.

       isnull         is a logical flag indicating whether the returned
                      column entry is null.
#### Parameters
       None.
#### Exceptions
       1)  If handle is invalid, the error will be diagnosed by routines
           called by this routine.

       2)  If segno is out of range, the error will diagnosed by routines
           called by this routine.

       3)  If recno is out of range, the error will diagnosed by routines
           called by this routine.

       4)  If column is not the name of a declared column, the error
           will be diagnosed by routines called by this routine.

       5)  If column specifies a column of whose data type is not
           double precision, the error SPICE(WRONGDATATYPE) will be
           signaled.

       6)  If column specifies a column of whose class is not a double precision
           class known to this routine, the error SPICE(NOCLASS) will be signaled.

       7)  If an attempt is made to read an uninitialized column entry,
           the error will be diagnosed by routines called by this
           routine.  A null entry is considered to be initialized, but
           entries do not contain null values by default.

       8)  If an I/O error occurs while reading the indicated file,
           the error will be diagnosed by routines called by this
           routine.

       9)  If the input column name string pointer is null, the error
           SPICE(NULLPOINTER) will be signaled.

       10) If the input column name string has length zero, the error
           SPICE(EMPTYSTRING) will be signaled.
#### Files
       See the EK Required Reading for a discussion of the EK file
       format.
#### Particulars
       This routine is a utility that allows an EK file to be read
       directly without using the high-level query interface.
#### Examples
       1)  Read the value in the third record of the column DCOL in
           the fifth segment of an EK file designated by HANDLE.

              #include "SpiceUsr.h"
                 .
                 .
                 .
              ekrced_c ( handle, 4, 2, "DCOL", &n, &dval, &isnull );
#### Restrictions
       1) EK files open for write access are not necessarily readable.
          In particular, a column entry can be read only if it has been
          initialized. The caller is responsible for determining
          when it is safe to read from files open for write access.
#### Literature_References
       None.
#### Author_and_Institution
       N.J. Bachman   (JPL)
#### Version
       -CSPICE Version 1.0.0, 04-JUL-2000 (NJB)
#### Index_Entries
       read double precision data from EK column
#### Link to routine ekrced_c source file ekrced_c.c

    Thu Apr 16 08:57:59 2009