| gcpool_c |
|
Table of contents
Procedure
gcpool_c (Get character data from the kernel pool)
void gcpool_c ( ConstSpiceChar * name,
SpiceInt start,
SpiceInt room,
SpiceInt cvalen,
SpiceInt * n,
void * cvals,
SpiceBoolean * found )
AbstractReturn the character value of a kernel variable from the kernel pool. Required_ReadingKERNEL KeywordsCONSTANTS FILES Brief_I/OVARIABLE I/O DESCRIPTION -------- --- -------------------------------------------------- name I Name of the variable whose value is to be returned. start I Which component to start retrieving for name room I The largest number of values to return. cvalen I The length of the output string. n O Number of values returned for name. cvals O Values associated with name. found O SPICETRUE if variable is in pool. Detailed_Input
name is the name of the variable whose values are to be
returned. If the variable is not in the pool with
character type, found will be SPICEFALSE.
start is the index of the first component of name to return.
The index follows the C convention of being 0 based.
If start is less than 0, it will be treated as 0. If
`start' is greater than the total number of components
available for name, no values will be returned (n will
be set to zero). However, found will still be set to
SPICETRUE.
room is the maximum number of components that should be
returned for this variable. (Usually it is the amount
of room available in the array cvals). If `room' is
less than 1 the error SPICE(BADARRAYSIZE) will be
signaled.
cvalen is the allowed length of the output string. This length
must large enough to hold the output string plus the
terminator. If the output string is expected to have x
characters, `cvalen' needs to be x + 1.
Detailed_Output
n is the number of values associated with name that
are returned. It will always be less than or equal
to room.
If name is not in the pool with character type, no
value is given to n.
cvals is the array of values associated with name.
If name is not in the pool with character type, no
values are given to the elements of cvals.
If the length of cvals is less than the length of
strings stored in the kernel pool (see MAXCHR) the
values returned will be truncated on the right.
found is SPICETRUE if the variable is in the pool and has
character type, SPICEFALSE if it is not.
Parameters
MAXCHR is the maximum number of characters that can be
stored in a component of a string valued kernel
variable. This value is currently 80.
Exceptions
1) If the value of `room' is less than one, the error
SPICE(BADARRAYSIZE) is signaled by a routine in the call tree
of this routine.
2) If `cvals' has declared length less than the size of a
string to be returned, the value will be truncated on
the right. See MAXCHR for the maximum stored size of
string variables.
3) If the `name' input string pointer is null, the error
SPICE(NULLPOINTER) is signaled.
4) If the `name' input string has zero length, the error
SPICE(EMPTYSTRING) is signaled.
5) If the `cvals' output string pointer is null, the error
SPICE(NULLPOINTER) is signaled.
6) If the `cvals' output string has length less than two
characters, the error SPICE(STRINGTOOSHORT) is signaled, since
the output string is too short to contain one character of
output data plus a null terminator.
FilesNone. ParticularsThis routine provides the user interface to retrieving character data stored in the kernel pool. This interface allows you to retrieve the data associated with a variable in multiple accesses. Under some circumstances this alleviates the problem of having to know in advance the maximum amount of space needed to accommodate all kernel variables. However, this method of access does come with a price. It is always more efficient to retrieve all of the data associated with a kernel pool data in one call than it is to retrieve it in sections. C requires the length of the output character array to be defined prior to calling the converted gcpool_c routine. The size of the cvals output array is user defined and passed as the variable cvalen. Also see the entry points gdpool_c and gipool_c. 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) The following code example demonstrates how the data stored
in a kernel pool variable can be retrieved in pieces.
Use the kernel shown below to load the kernel pool with the
variables used within the example.
KPL/MK
File name: gcpool_ex1.tm
This kernel is intended to support operation of SPICE
example programs.
\begindata
CTEST_VAL = ('LARRY', 'MOE', 'CURLY' )
ITEST_VAL = ( 3141, 186, 282 )
DTEST_VAL = ( 3.1415, 186. , 282.397 )
\begintext
End of meta-kernel
Example code begins here.
/.
Program gcpool_ex1
./
#include <stdio.h>
#include "SpiceUsr.h"
int main()
{
/.
Local parameters.
./
#define LENOUT 20
#define NUMVALS 2
#define START 1
/.
Local variables
./
SpiceBoolean found;
SpiceChar cvals[NUMVALS][LENOUT];
SpiceInt i;
SpiceInt n;
/.
Load the test data.
./
furnsh_c ( "gcpool_ex1.tm" );
/.
Get NUMVALS values starting at the START value
in the list. Each value will be of length LENOUT.
./
gcpool_c ( "CTEST_VAL", START, NUMVALS, LENOUT, &n, cvals,
&found );
for ( i = 0; i < NUMVALS; i++ )
{
printf("%s\n", cvals[i] );
}
return ( 0 );
}
When this program was executed on a Mac/Intel/cc/64-bit
platform, the output was:
MOE
CURLY
RestrictionsNone. Literature_ReferencesNone. Author_and_InstitutionJ. Diaz del Rio (ODC Space) W.L. Taber (JPL) E.D. Wright (JPL) Version
-CSPICE Version 2.3.0, 10-AUG-2021 (JDR)
Changed the input argument name "lenout" to "cvalen" for
consistency with other routines.
Edited the header to comply with NAIF standard.
Removed unnecessary include statements from code example and
replaced "ldpool_c" by "furnsh_c".
Added MAXCHR parameter description. Updated entry #2 in and
added entry #5 to -Exceptions section.
-CSPICE Version 2.2.1, 07-SEP-2007 (EDW)
Edited the 'lenout' description in the -Detailed_Input to
remove the recommendation of 32 as a general use value
for 'lenout'.
-CSPICE Version 2.2.0, 18-MAY-2001 (WLT)
Added a cast to (char *) in the call to F2C_ConvertStrArr.
-CSPICE Version 2.1.0, 22-JUN-1999 (EDW)
Added local variable to return boolean/logical values. This
fix allows the routine to function if int and long are different
sizes.
-CSPICE Version 2.0.3, 09-FEB-1998 (EDW)
Removed the output dynamically allocated string. Conversion
of cval from string to array now accomplished via the
F2C_ConvertStrArray call.
-CSPICE Version 2.0.2, 01-FEB-1998 (EDW)
Removed the input and work dynamically allocated strings.
-CSPICE Version 2.0.1, 28-JAN-1998 (EDW)
The start parameter is now zero based as per C convention.
Adjusted the amount of memory for the strings to cvalen-1.
-CSPICE Version 2.0.0, 07-JAN-1998 (EDW)
The routine now function properly for room > 1. Previously
only a single value could be returned.
-CSPICE Version 1.0.0, 23-OCT-1997 (EDW)
Index_EntriesRETURN the character value of a pooled kernel variable RETURN the string value of a pooled kernel variable |
Fri Dec 31 18:41:07 2021