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diff --git a/src/slalib/cc2s.f b/src/slalib/cc2s.f
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+      SUBROUTINE sla_CC2S (V, A, B)
+*+
+*     - - - - -
+*      C C 2 S
+*     - - - - -
+*
+*  Direction cosines to spherical coordinates (single precision)
+*
+*  Given:
+*     V     r(3)   x,y,z vector
+*
+*  Returned:
+*     A,B   r      spherical coordinates in radians
+*
+*  The spherical coordinates are longitude (+ve anticlockwise
+*  looking from the +ve latitude pole) and latitude.  The
+*  Cartesian coordinates are right handed, with the x axis
+*  at zero longitude and latitude, and the z axis at the
+*  +ve latitude pole.
+*
+*  If V is null, zero A and B are returned.
+*  At either pole, zero A is returned.
+*
+*  P.T.Wallace   Starlink   July 1989
+*
+*  Copyright (C) 1995 Rutherford Appleton Laboratory
+*-
+
+      IMPLICIT NONE
+
+      REAL V(3),A,B
+
+      REAL X,Y,Z,R
+
+
+      X = V(1)
+      Y = V(2)
+      Z = V(3)
+      R = SQRT(X*X+Y*Y)
+
+      IF (R.EQ.0.0) THEN
+         A = 0.0
+      ELSE
+         A = ATAN2(Y,X)
+      END IF
+
+      IF (Z.EQ.0.0) THEN
+         B = 0.0
+      ELSE
+         B = ATAN2(Z,R)
+      END IF
+
+      END