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slalib/kbj.f

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+      SUBROUTINE sla_KBJ (JB, E, K, J)
+*+
+*     - - - -
+*      K B J
+*     - - - -
+*
+*  Select epoch prefix 'B' or 'J'
+*
+*  Given:
+*     JB     int     sla_DBJIN prefix status:  0=none, 1='B', 2='J'
+*     E      dp      epoch - Besselian or Julian
+*
+*  Returned:
+*     K      char    'B' or 'J'
+*     J      int     status:  0=OK
+*
+*  If JB=0, B is assumed for E < 1984D0, otherwise J.
+*
+*  P.T.Wallace   Starlink   31 July 1989
+*
+*  Copyright (C) 1995 Rutherford Appleton Laboratory
+*
+*  License:
+*    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 (see SLA_CONDITIONS); if not, write to the 
+*    Free Software Foundation, Inc., 59 Temple Place, Suite 330, 
+*    Boston, MA  02111-1307  USA
+*
+*-
+
+      IMPLICIT NONE
+
+      INTEGER JB
+      DOUBLE PRECISION E
+      CHARACTER K*(*)
+      INTEGER J
+
+*  Preset status
+      J=0
+
+*  If prefix given expressly, use it
+      IF (JB.EQ.1) THEN
+         K='B'
+      ELSE IF (JB.EQ.2) THEN
+         K='J'
+
+*  If no prefix, examine the epoch
+      ELSE IF (JB.EQ.0) THEN
+
+*     If epoch is pre-1984.0, assume Besselian;  otherwise Julian
+         IF (E.LT.1984D0) THEN
+            K='B'
+         ELSE
+            K='J'
+         END IF
+
+*  If illegal prefix, return error status
+      ELSE
+         K=' '
+         J=1
+      END IF
+
+      END