diff --git a/func_proc/coreneuron/func_proc.cpp b/func_proc/coreneuron/func_proc.cpp
index 9b019fb..4c87abc 100644
--- a/func_proc/coreneuron/func_proc.cpp
+++ b/func_proc/coreneuron/func_proc.cpp
@@ -205,7 +205,7 @@ namespace coreneuron {
     }
 
 
-    inline double get_a_42_test_func_proc(int id, int pnodecount, test_func_proc_Instance* inst, double* data, const Datum* indexes, ThreadDatum* thread, NrnThread* nt, double v, double a);
+    inline double x_plus_a_test_func_proc(int id, int pnodecount, test_func_proc_Instance* inst, double* data, const Datum* indexes, ThreadDatum* thread, NrnThread* nt, double v, double a);
     inline int set_x_42_test_func_proc(int id, int pnodecount, test_func_proc_Instance* inst, double* data, const Datum* indexes, ThreadDatum* thread, NrnThread* nt, double v);
     inline int set_x_a_test_func_proc(int id, int pnodecount, test_func_proc_Instance* inst, double* data, const Datum* indexes, ThreadDatum* thread, NrnThread* nt, double v, double a);
     inline int set_a_x_test_func_proc(int id, int pnodecount, test_func_proc_Instance* inst, double* data, const Datum* indexes, ThreadDatum* thread, NrnThread* nt, double v);
@@ -233,10 +233,10 @@ namespace coreneuron {
     }
 
 
-    inline double get_a_42_test_func_proc(int id, int pnodecount, test_func_proc_Instance* inst, double* data, const Datum* indexes, ThreadDatum* thread, NrnThread* nt, double v, double a) {
-        double ret_get_a_42 = 0.0;
-        ret_get_a_42 = a + 42.0;
-        return ret_get_a_42;
+    inline double x_plus_a_test_func_proc(int id, int pnodecount, test_func_proc_Instance* inst, double* data, const Datum* indexes, ThreadDatum* thread, NrnThread* nt, double v, double a) {
+        double ret_x_plus_a = 0.0;
+        ret_x_plus_a = inst->x[id] + a;
+        return ret_x_plus_a;
     }
 
 
diff --git a/func_proc/neuron/func_proc.cpp b/func_proc/neuron/func_proc.cpp
index 6168482..07af4cd 100644
--- a/func_proc/neuron/func_proc.cpp
+++ b/func_proc/neuron/func_proc.cpp
@@ -121,7 +121,7 @@ namespace neuron {
         hoc_retpushx(1.);
     }
     /* Mechanism procedures and functions */
-    inline double get_a_42_test_func_proc(_nrn_mechanism_cache_range* _ml, size_t id, Datum* _ppvar, Datum* _thread, NrnThread* _nt, double a);
+    inline double x_plus_a_test_func_proc(_nrn_mechanism_cache_range* _ml, size_t id, Datum* _ppvar, Datum* _thread, NrnThread* _nt, double a);
     inline int set_x_42_test_func_proc(_nrn_mechanism_cache_range* _ml, size_t id, Datum* _ppvar, Datum* _thread, NrnThread* _nt);
     inline int set_x_a_test_func_proc(_nrn_mechanism_cache_range* _ml, size_t id, Datum* _ppvar, Datum* _thread, NrnThread* _nt, double a);
     inline int set_a_x_test_func_proc(_nrn_mechanism_cache_range* _ml, size_t id, Datum* _ppvar, Datum* _thread, NrnThread* _nt);
@@ -143,11 +143,11 @@ namespace neuron {
     static void _hoc_set_x_42(void);
     static void _hoc_set_x_a(void);
     static void _hoc_set_a_x(void);
-    static void _hoc_get_a_42(void);
+    static void _hoc_x_plus_a(void);
     static double _npy_set_x_42(Prop*);
     static double _npy_set_x_a(Prop*);
     static double _npy_set_a_x(Prop*);
-    static double _npy_get_a_42(Prop*);
+    static double _npy_x_plus_a(Prop*);
 
 
     /* connect user functions to hoc names */
@@ -156,14 +156,14 @@ namespace neuron {
         {"set_x_42_test_func_proc", _hoc_set_x_42},
         {"set_x_a_test_func_proc", _hoc_set_x_a},
         {"set_a_x_test_func_proc", _hoc_set_a_x},
-        {"get_a_42_test_func_proc", _hoc_get_a_42},
+        {"x_plus_a_test_func_proc", _hoc_x_plus_a},
         {0, 0}
     };
     static NPyDirectMechFunc npy_direct_func_proc[] = {
         {"set_x_42", _npy_set_x_42},
         {"set_x_a", _npy_set_x_a},
         {"set_a_x", _npy_set_a_x},
-        {"get_a_42", _npy_get_a_42},
+        {"x_plus_a", _npy_x_plus_a},
     };
     static void _hoc_set_x_42(void) {
         double _r{};
@@ -267,22 +267,25 @@ namespace neuron {
         set_a_x_test_func_proc(_ml, id, _ppvar, _thread, _nt);
         return(_r);
     }
-    static void _hoc_get_a_42(void) {
+    static void _hoc_x_plus_a(void) {
         double _r{};
         Datum* _ppvar;
         Datum* _thread;
         NrnThread* _nt;
-        Prop* _local_prop = _prop_id ? _extcall_prop : nullptr;
+        if (!_prop_id) {
+            hoc_execerror("No data for x_plus_a_test_func_proc. Requires prior call to setdata_test_func_proc and that the specified mechanism instance still be in existence.", NULL);
+        }
+        Prop* _local_prop = _extcall_prop;
         _nrn_mechanism_cache_instance _ml_real{_local_prop};
         auto* const _ml = &_ml_real;
         size_t const id{};
         _ppvar = _local_prop ? _nrn_mechanism_access_dparam(_local_prop) : nullptr;
         _thread = _extcall_thread.data();
         _nt = nrn_threads;
-        _r = get_a_42_test_func_proc(_ml, id, _ppvar, _thread, _nt, *getarg(1));
+        _r = x_plus_a_test_func_proc(_ml, id, _ppvar, _thread, _nt, *getarg(1));
         hoc_retpushx(_r);
     }
-    static double _npy_get_a_42(Prop* _prop) {
+    static double _npy_x_plus_a(Prop* _prop) {
         double _r{};
         Datum* _ppvar;
         Datum* _thread;
@@ -293,7 +296,7 @@ namespace neuron {
         _ppvar = _nrn_mechanism_access_dparam(_prop);
         _thread = _extcall_thread.data();
         _nt = nrn_threads;
-        _r = get_a_42_test_func_proc(_ml, id, _ppvar, _thread, _nt, *getarg(1));
+        _r = x_plus_a_test_func_proc(_ml, id, _ppvar, _thread, _nt, *getarg(1));
         return(_r);
     }
 
@@ -323,11 +326,11 @@ namespace neuron {
     }
 
 
-    inline double get_a_42_test_func_proc(_nrn_mechanism_cache_range* _ml, size_t id, Datum* _ppvar, Datum* _thread, NrnThread* _nt, double a) {
+    inline double x_plus_a_test_func_proc(_nrn_mechanism_cache_range* _ml, size_t id, Datum* _ppvar, Datum* _thread, NrnThread* _nt, double a) {
         auto inst = make_instance_test_func_proc(*_ml);
-        double ret_get_a_42 = 0.0;
-        ret_get_a_42 = a + 42.0;
-        return ret_get_a_42;
+        double ret_x_plus_a = 0.0;
+        ret_x_plus_a = inst.x[id] + a;
+        return ret_x_plus_a;
     }
 
 
diff --git a/func_proc_pnt/coreneuron/func_proc_pnt.cpp b/func_proc_pnt/coreneuron/func_proc_pnt.cpp
index 9644888..4ebe283 100644
--- a/func_proc_pnt/coreneuron/func_proc_pnt.cpp
+++ b/func_proc_pnt/coreneuron/func_proc_pnt.cpp
@@ -210,7 +210,7 @@ namespace coreneuron {
     }
 
 
-    inline double get_a_42_test_func_proc_pnt(int id, int pnodecount, test_func_proc_pnt_Instance* inst, double* data, const Datum* indexes, ThreadDatum* thread, NrnThread* nt, double v, double a);
+    inline double x_plus_a_test_func_proc_pnt(int id, int pnodecount, test_func_proc_pnt_Instance* inst, double* data, const Datum* indexes, ThreadDatum* thread, NrnThread* nt, double v, double a);
     inline int set_x_42_test_func_proc_pnt(int id, int pnodecount, test_func_proc_pnt_Instance* inst, double* data, const Datum* indexes, ThreadDatum* thread, NrnThread* nt, double v);
     inline int set_x_a_test_func_proc_pnt(int id, int pnodecount, test_func_proc_pnt_Instance* inst, double* data, const Datum* indexes, ThreadDatum* thread, NrnThread* nt, double v, double a);
 
@@ -229,10 +229,10 @@ namespace coreneuron {
     }
 
 
-    inline double get_a_42_test_func_proc_pnt(int id, int pnodecount, test_func_proc_pnt_Instance* inst, double* data, const Datum* indexes, ThreadDatum* thread, NrnThread* nt, double v, double a) {
-        double ret_get_a_42 = 0.0;
-        ret_get_a_42 = a + 42.0;
-        return ret_get_a_42;
+    inline double x_plus_a_test_func_proc_pnt(int id, int pnodecount, test_func_proc_pnt_Instance* inst, double* data, const Datum* indexes, ThreadDatum* thread, NrnThread* nt, double v, double a) {
+        double ret_x_plus_a = 0.0;
+        ret_x_plus_a = inst->x[id] + a;
+        return ret_x_plus_a;
     }
 
 
diff --git a/func_proc_pnt/neuron/func_proc_pnt.cpp b/func_proc_pnt/neuron/func_proc_pnt.cpp
index 9ba13ea..694c4f8 100644
--- a/func_proc_pnt/neuron/func_proc_pnt.cpp
+++ b/func_proc_pnt/neuron/func_proc_pnt.cpp
@@ -143,7 +143,7 @@ namespace neuron {
         _setdata(_prop);
     }
     /* Mechanism procedures and functions */
-    inline double get_a_42_test_func_proc_pnt(_nrn_mechanism_cache_range* _ml, size_t id, Datum* _ppvar, Datum* _thread, NrnThread* _nt, double a);
+    inline double x_plus_a_test_func_proc_pnt(_nrn_mechanism_cache_range* _ml, size_t id, Datum* _ppvar, Datum* _thread, NrnThread* _nt, double a);
     inline int set_x_42_test_func_proc_pnt(_nrn_mechanism_cache_range* _ml, size_t id, Datum* _ppvar, Datum* _thread, NrnThread* _nt);
     inline int set_x_a_test_func_proc_pnt(_nrn_mechanism_cache_range* _ml, size_t id, Datum* _ppvar, Datum* _thread, NrnThread* _nt, double a);
 
@@ -163,7 +163,7 @@ namespace neuron {
     /* declaration of user functions */
     static double _hoc_set_x_42(void*);
     static double _hoc_set_x_a(void*);
-    static double _hoc_get_a_42(void*);
+    static double _hoc_x_plus_a(void*);
 
 
     /* connect user functions to hoc names */
@@ -176,7 +176,7 @@ namespace neuron {
         {"get_loc", _hoc_get_loc_pnt},
         {"set_x_42", _hoc_set_x_42},
         {"set_x_a", _hoc_set_x_a},
-        {"get_a_42", _hoc_get_a_42},
+        {"x_plus_a", _hoc_x_plus_a},
         {0, 0}
     };
     static double _hoc_set_x_42(void* _vptr) {
@@ -219,7 +219,7 @@ namespace neuron {
         set_x_a_test_func_proc_pnt(_ml, id, _ppvar, _thread, _nt, *getarg(1));
         return(_r);
     }
-    static double _hoc_get_a_42(void* _vptr) {
+    static double _hoc_x_plus_a(void* _vptr) {
         double _r{};
         Datum* _ppvar;
         Datum* _thread;
@@ -235,7 +235,7 @@ namespace neuron {
         _ppvar = _nrn_mechanism_access_dparam(_p);
         _thread = _extcall_thread.data();
         _nt = static_cast<NrnThread*>(_pnt->_vnt);
-        _r = get_a_42_test_func_proc_pnt(_ml, id, _ppvar, _thread, _nt, *getarg(1));
+        _r = x_plus_a_test_func_proc_pnt(_ml, id, _ppvar, _thread, _nt, *getarg(1));
         return(_r);
     }
 
@@ -256,11 +256,11 @@ namespace neuron {
     }
 
 
-    inline double get_a_42_test_func_proc_pnt(_nrn_mechanism_cache_range* _ml, size_t id, Datum* _ppvar, Datum* _thread, NrnThread* _nt, double a) {
+    inline double x_plus_a_test_func_proc_pnt(_nrn_mechanism_cache_range* _ml, size_t id, Datum* _ppvar, Datum* _thread, NrnThread* _nt, double a) {
         auto inst = make_instance_test_func_proc_pnt(*_ml);
-        double ret_get_a_42 = 0.0;
-        ret_get_a_42 = a + 42.0;
-        return ret_get_a_42;
+        double ret_x_plus_a = 0.0;
+        ret_x_plus_a = inst.x[id] + a;
+        return ret_x_plus_a;
     }