Table of contents
CSPICE_DAFOPW opens a DAF for subsequent write requests.
Given:
fname the scalar string name of a DAF to open for read/write access.
help, fname
STRING = Scalar
the call:
cspice_dafopw, fname, handle
returns:
handle scalar integer value other DAF routines use to refer to `fname'.
help, handle
LONG = Scalar
None.
Any numerical results shown for this example may differ between
platforms as the results depend on the SPICE kernels used as input
and the machine specific arithmetic implementation.
1) Delete the entire comment area of a DAF file. Note that this
action should only be performed if fresh new comments are to
be placed within the DAF file.
Use the SPK kernel below as input DAF file for the program.
earthstns_itrf93_201023.bsp
Example code begins here.
PRO dafopw_ex1
;;
;; Local parameters
;;
KERNEL = 'earthstns_itrf93_201023.bsp'
BUFFSZ = 10
LINLEN = 1000
;;
;; Open a DAF for write. Return a `handle' referring to the
;; file.
;;
cspice_dafopw, KERNEL, handle
;;
;; Print the first 10 lines of comments from the DAF file.
;;
print, 'Comment area of input DAF file (max. 10 lines): '
print, '-------------------------------' + $
'-------------------------------'
cspice_dafec, handle, BUFFSZ, LINLEN, n, buffer, done
for i=0, n - 1L do begin
print, buffer[i]
endfor
print, '-------------------------------' + $
'-------------------------------'
print, ' '
print, 'Deleting entire comment area...'
;;
;; Delete all the comments from the DAF file.
;;
cspice_dafdc, handle
;;
;; Close the DAF file and re-open it for read
;; access to work around the cspice_dafec restriction
;; on comments not to be modified while they are
;; being extracted.
;;
cspice_dafcls, handle
cspice_dafopr, KERNEL, handle
;;
;; Check if the comments have indeed been deleted.
;;
cspice_dafec, handle, BUFFSZ, LINLEN, n, buffer, done
if ( ( done ) and ( n eq 0 ) ) then begin
print, ' '
print, ' Successful operation.'
endif else begin
print, ' '
print, ' Operation failed.'
endelse
;;
;; Safely close the DAF.
;;
cspice_dafcls, handle
END
When this program was executed on a Mac/Intel/IDL8.x/64-bit
platform, the output was:
Comment area of input DAF file (max. 10 lines):
--------------------------------------------------------------
SPK for DSN Station Locations
=====================================================================
Original file name: earthstns_itrf93_201023.bsp
Creation date: 2020 October 28 12:30
Created by: Nat Bachman (NAIF/JPL)
Introduction
--------------------------------------------------------------
Deleting entire comment area...
Successful operation.
Most DAFs require only read access. If you do not need to
change the contents of a file, you should open it with cspice_dafopr.
Use cspice_dafopw when you need to
-- change (update) one or more summaries, names, or
arrays within a file; or
-- add new arrays to a file.
Use cspice_dafcls to close files opened by this routine.
1) If the specified file has already been opened, either by the
DAF routines or by other code, an error is signaled by a
routine in the call tree of this routine. Note that this
response is not paralleled by cspice_dafopr, which allows you to open
a DAF for reading even if it is already open for reading.
2) If the specified file cannot be opened without exceeding the
maximum number of files, the error SPICE(DAFFTFULL) is
signaled by a routine in the call tree of this routine.
3) If the attempt to read the file's file record fails, the error
SPICE(FILEREADFAILED) is signaled by a routine in the call
tree of this routine.
4) If the specified file is not a DAF file, an error is signaled
by a routine in the call tree of this routine.
5) If no logical units are available, an error is signaled by a
routine in the call tree of this routine.
6) If the file does not exist, an error is signaled by a routine
in the call tree of this routine.
7) If an I/O error occurs in the process of opening the file, the
error is signaled by a routine in the call tree of this
routine.
8) If the file name is blank or otherwise inappropriate, an error
is signaled by a routine in the call tree of this routine.
9) If the file was transferred improperly via FTP, an error is
signaled by a routine in the call tree of this routine.
10) If the file utilizes a non-native binary file format, an error
is signaled by a routine in the call tree of this routine.
11) If the input argument `fname' is undefined, an error is
signaled by the IDL error handling system.
12) If the input argument `fname' is not of the expected type, or
it does not have the expected dimensions and size, an error is
signaled by the Icy interface.
13) If the output argument `handle' is not a named variable, an
error is signaled by the Icy interface.
See argument `fname'.
1) Only files of the native binary file format may be opened
with this routine.
2) Files opened using this routine must be closed with cspice_dafcls.
DAF.REQ
ICY.REQ
None.
J. Diaz del Rio (ODC Space)
E.D. Wright (JPL)
-Icy Version 1.0.2, 25-NOV-2021 (JDR)
Edited the header to comply with NAIF standard. Added complete
code example.
Added -Parameters, -Exceptions, -Files, -Restrictions,
-Literature_References and -Author_and_Institution sections, and
completed -Particulars section.
Removed reference to the routine's corresponding CSPICE header from
-Abstract section.
Added arguments' type and size information in the -I/O section.
-Icy Version 1.0.1, 13-SEP-2012 (EDW)
Edits and clean up to header text.
-Icy Version 1.0.0, 08-DEC-2004 (EDW)
open existing DAF for write
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