Some simplifications, more work on error handling and setting errno c…

…onsistently

include/novas.h

@@ -753,6 +753,12 @@ int place_gcrs(double jd_tt, const object *source, enum novas_accuracy accuracy,
 
 int place_cirs(double jd_tt, const object *source, enum novas_accuracy accuracy, sky_pos *pos);
 
+int radec_star(double jd_tt, const cat_entry *star, const observer *obs, double ut1_to_tt, enum novas_reference_system sys,
+        enum novas_accuracy accuracy, double *ra, double *dec, double *rv);
+
+int radec_planet(double jd_tt, const object *ss_body, const observer *obs, double ut1_to_tt, enum novas_reference_system sys,
+        enum novas_accuracy accuracy, double *ra, double *dec, double *dis, double *rv);
+
 double refract_astro(const on_surface *location, enum novas_refraction_model option, double zd_calc);
 
 int light_time2(double jd_tdb, const object *ss_object, const double *pos_obs, double tlight0, enum novas_accuracy accuracy, double *prel,

include/nutation.h

@@ -27,22 +27,23 @@
  *                    for normal (reduced) precision.
  * @param[out] dpsi   [rad] δψ Nutation (luni-solar + planetary) in longitude, in radians.
  * @param[out] deps   [rad] δε Nutation (luni-solar + planetary) in obliquity, in radians.
+ * @return            0 if successful, or else -1 (errno should be set to indicate the type of error).
  *
  * @sa nutation()
  * @sa iau2000a()
  * @sa iau2000b()
  * @sa iau2000k()
  */
-typedef void (*novas_nutate_func)(double jd_tt_high, double jd_tt_low, double *dpsi, double *deps);
+typedef int (*novas_nutate_func)(double jd_tt_high, double jd_tt_low, double *dpsi, double *deps);
 
 
-void iau2000a(double jd_tt_high, double jd_tt_low, double *dpsi, double *deps);
+int iau2000a(double jd_tt_high, double jd_tt_low, double *dpsi, double *deps);
 
 
-void iau2000b(double jd_tt_high, double jd_tt_low, double *dpsi, double *deps);
+int iau2000b(double jd_tt_high, double jd_tt_low, double *dpsi, double *deps);
 
 
-void nu2000k(double jd_tt_high, double jd_tt_low, double *dpsi, double *deps);
+int nu2000k(double jd_tt_high, double jd_tt_low, double *dpsi, double *deps);