; ERROR
;---------------------------------------------------------------
;! was there an error
;# ADVERB POPS CATALOG
;-----------------------------------------------------------------------
;;  Copyright (C) 1995, 2020
;;  Associated Universities, Inc. Washington DC, USA.
;;
;;  This program is free software; you can redistribute it and/or
;;  modify it under the terms of the GNU General Public License as
;;  published by the Free Software Foundation; either version 2 of
;;  the License, or (at your option) any later version.
;;
;;  This program is distributed in the hope that it will be useful,
;;  but WITHOUT ANY WARRANTY; without even the implied warranty of
;;  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;  GNU General Public License for more details.
;;
;;  You should have received a copy of the GNU General Public
;;  License along with this program; if not, write to the Free
;;  Software Foundation, Inc., 675 Massachusetts Ave, Cambridge,
;;  MA 02139, USA.
;;
;;  Correspondence concerning AIPS should be addressed as follows:
;;         Internet email: aipsmail@nrao.edu.
;;         Postal address: AIPS Project Office
;;                         National Radio Astronomy Observatory
;;                         520 Edgemont Road
;;                         Charlottesville, VA 22903-2475 USA
;-----------------------------------------------------------------------
ERROR     LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC
----------------------------------------------------------------
ERROR
Type:  Adverb  (scalar)
Use:   Was there an error?  Also used as an estimate of the uncertainty
       in some tasks.
Null value:
       none.  <= 0 => false,   > 0 => true.
       or 0 => task-dependent default
Verbs:
   CHKNAME.....Checks existence of data set or image by name adverbs
   COPIXEL.....Convert between physical and pixel coordinate values.
   EGETHEAD....Returns parameter value from image header and error
               code.
   EGETNAME....Gets INNAME et al., setting ERROR true on empty slot.
   FILEZAP.....Delete an external file,
   GETVERS.....Finds maximum version number of an extension file.
   IMCENTER....Returns pixel position of sub-image centroid,
   IMVAL.......Does cubic interpolation of image value; returns ERROR
               true if fit failed.
   MAXFIT......Finds coordinates and value of an image extremum;
               returns ERROR true if fit failed.
   NAMEGET.....Fills 1st input image name parameters by default
               matching.
   QGETVERS....Finds maximum version number of an extension file
               quietly.
   QIMVAL......Does cubic interpolation of image value quietly; returns
               ERROR true if fit failed.
   SYSTEM......Verb to send a command to the operating system.
Procedures:
   TVFLUX......Displays coordinates and values selected with the TV
               cursor; sets ERROR true if cubic interpolation fails.
   TVMAXFIT....Displays fit pixel positions and intensity at maxima on
               TV; returns ERROR true if MAXFIT fails on a position.
Tasks:
   BSMAP.......Images weak sources with closure phases.  ERROR is the
               error per unit weight in Jy.
   FITLD.......Reads FITS files to load images or UV (IDI or UVFITS)
               data to disk.  ERROR >= 2 on input means to ignore AIPS
               history (useful if the data were written by FITAB once
               and then FITTP).
   IMLOD.......Reads tape to load images to disk.  ERROR as in FITLD.
   PRTTP.......Prints contents of tapes and disk files, all supported
               formats.  ERROR as in FITLD.
   UVLOD.......Read export or FITS data from a tape or disk.  ERROR as
               in FITLD.
----------------------------------------------------------------