Table of contents
wnfetd_c ( Fetch an interval from a DP window )
void wnfetd_c ( SpiceCell * window,
SpiceDouble * left,
SpiceDouble * right )
Fetch a particular interval from a double precision window.
VARIABLE I/O DESCRIPTION
-------- --- --------------------------------------------------
window I Input window.
n I Index of interval to be fetched.
right O Left, right endpoints of the nth interval.
window is a window containing zero or more intervals.
`window' must be declared as a double precision SpiceCell.
CSPICE provides the following macro, which declares and
initializes the cell
SPICEDOUBLE_CELL ( window, WINDOWSZ );
where WINDOWSZ is the maximum capacity of `window'.
n is the index of a particular interval within the window.
Indices range from 0 to NINT-1, where NINT is the number of
intervals in the window (card_c(&window)/2).
right are the left and right endpoints of the N'th interval in
the input window. If the interval is not found, `left' and
`right' are not defined.
1) If `n' is less than one, the error SPICE(NOINTERVAL) is
signaled by a routine in the call tree of this routine.
2) If the interval does not exist, i.e. n > card_c(window)/2, the
error SPICE(NOINTERVAL) is signaled by a routine in the call
tree of this routine.
3) The cardinality of the input `window' must be even. Left
endpoints of stored intervals must be strictly greater than
preceding right endpoints. Right endpoints must be greater
than or equal to corresponding left endpoints. Invalid window
data are not diagnosed by this routine and may lead to
4) If the `window' cell argument has a type other than
SpiceDouble, the error SPICE(TYPEMISMATCH) is signaled.
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
1) The following code example demonstrates how to insert an
interval into an existing double precision SPICE window, and
how to loop over all its intervals to extract their left and
Example code begins here.
#define WNSIZE 10
SPICEDOUBLE_CELL ( window, WNSIZE );
Validate the window with size WNSIZE and zero elements.
wnvald_c ( WNSIZE, 0, &window );
Insert the intervals
[ 1, 3 ] [ 7, 11 ] [ 23, 27 ]
wninsd_c ( 1.0, 3.0, &window );
wninsd_c ( 7.0, 11.0, &window );
wninsd_c ( 23.0, 27.0, &window );
Loop over the number of intervals in `window', output
the `left' and `right' endpoints for each interval.
for ( i=0; i<wncard_c(&window); i++)
wnfetd_c( &window, i, &left, &right );
printf("Interval %d [%8.3f, %8.3f]\n", i, left, right );
return ( 0 );
When this program was executed on a Mac/Intel/cc/64-bit
platform, the output was:
Interval 0 [ 1.000, 3.000]
Interval 1 [ 7.000, 11.000]
Interval 2 [ 23.000, 27.000]
N.J. Bachman (JPL)
J. Diaz del Rio (ODC Space)
W.L. Taber (JPL)
I.M. Underwood (JPL)
E.D. Wright (JPL)
-CSPICE Version 1.0.2, 10-AUG-2021 (JDR)
Edited the header to comply to NAIF standard. Added complete code
example, problem statement and solution.
Extended description of argument "window" in -Detailed_Input to include
type and preferred declaration method.
Added entry #3 in -Exceptions section.
-CSPICE Version 1.0.1, 30-JUL-2007 (EDW)
Removed erroneous description in the -Examples section
indicating "Undefined" as a return state after an error
event caused by an invalid value of n.
-CSPICE Version 1.0.0, 22-AUG-2002 (NJB) (WLT) (IMU)
fetch an interval from a d.p. window