Add function ngSpice_Reset(void) to completely reset shared ngspice,

so that it may be restartet again by ngSpice_Init

src/include/ngspice/sharedspice.h

@@ -96,6 +96,10 @@ Locking and unlocking the realloc of output vectors during simulation. May be se
 during reading output vectors in the primary thread, while the simulation in the
 background thread is moving on.
 
+**
+int ngSpice_Reset(void)
+Reset ngspice as far as possible
+
 **
 Additional basics:
 No memory mallocing and freeing across the interface:

src/sharedspice.c

@@ -352,6 +352,20 @@ static char* outstorage(char*, bool);
 static void printsend(void);
 #endif
 
+static int totalreset(void);
+extern void rem_controls(void);
+extern void destroy_wallace(void);
+extern void sh_delete_myvec(void);
+extern IFsimulator SIMinfo;
+extern void spice_destroy_devices(void); /* FIXME need a better place */
+
+extern void destroy_const_plot(void);
+extern void com_destroy(wordlist* wl);
+extern void com_unalias(wordlist* wl);
+extern void com_undefine(wordlist* wl);
+extern void com_remcirc(wordlist* wl);
+extern void unset_all(void);
+
 #include "ngspice/sharedspice.h"
 
 static SendChar* pfcn;
@@ -1367,6 +1381,12 @@ int ngSpice_UnlockRealloc(void)
     return 1;
 }
 
+/* Reset ngspice as far as possible */
+IMPEXP
+int ngSpice_Reset(void)
+{
+    return totalreset();
+}
 
 /* add the preliminary breakpoints to the list.
    called from dctran.c */
@@ -2034,12 +2054,12 @@ ATTRIBUTE_NORETURN void shared_exit(int status)
       hand this information over to caller */
     if (status >= 1000) {
         coquit = TRUE;
-        fprintf(stdout, "\nNote: 'quit' asks for detaching ngspice.dll.\n");
+        fprintf(stdout, "\nNote: 'quit' asks for resetting or detaching ngspice.dll.\n");
         status -= 1000;
     }
     else {
         coquit = FALSE;
-        fprintf(stderr, "Error: ngspice.dll cannot recover and awaits to be detached\n");
+        fprintf(stderr, "Error: ngspice.dll cannot recover and awaits to be reset or detached\n");
     }
 #ifndef low_latency
     // set flag to stop the printsend thread
@@ -2402,3 +2422,86 @@ void shared_send_dict(int index, int no_of_nodes, char* name, char*type)
         sendinitevt(index, no_of_nodes, name, type, ng_ident, euserptr);
 }
 #endif
+
+static int totalreset(void)
+{
+    if(!is_initialized)
+        return 1;
+
+    is_initialized = FALSE;
+
+    /* start to clean up the mess */
+
+    noprintfwanted = FALSE;
+    nostatuswanted = FALSE;
+    nodatawanted = FALSE;
+    nodatainitwanted = FALSE;
+    nobgtrwanted = FALSE;
+    wantvdat = FALSE;
+    wantidat = FALSE;
+    wantsync = FALSE;
+    immediate = FALSE;
+    coquit = FALSE;
+
+#ifdef THREADS
+/* Destroy the mutexes */
+#ifdef HAVE_LIBPTHREAD
+    pthread_mutex_destroy(&triggerMutex);
+    pthread_mutex_destroy(&allocMutex);
+    pthread_mutex_destroy(&fputsMutex);
+    pthread_mutex_destroy(&vecreallocMutex);
+    cont_condition = FALSE;
+#else
+#ifdef SRW
+    /* Do we need to remove the SWR locks? */
+//    InitializeSRWLock(&triggerMutex);
+//    InitializeSRWLock(&allocMutex);
+//    InitializeSRWLock(&fputsMutex);
+//    InitializeSRWLock(&vecreallocMutex);
+#else
+    DeleteCriticalSection(&triggerMutex);
+    DeleteCriticalSection(&allocMutex);
+    DeleteCriticalSection(&fputsMutex);
+    DeleteCriticalSection(&vecreallocMutex);
+#endif
+#endif
+    // Id of primary thread
+    main_id = 0;
+#endif
+
+    wordlist all = { "all", NULL, NULL };
+    wordlist star = { "*", NULL, NULL };
+
+    com_destroy(&all);
+    com_unalias(&star);
+    com_undefine(&star);
+
+    cp_remvar("history");
+    cp_remvar("noglob");
+    cp_remvar("brief");
+    cp_remvar("sourcepath");
+    cp_remvar("program");
+    cp_remvar("prompt");
+
+    destroy_wallace();
+
+    rem_controls();
+
+    while (ft_curckt) {
+        wl_delete(ft_curckt->ci_sourceinfo);
+        com_remcirc(NULL);
+    }
+
+    cp_destroy_keywords();
+    destroy_ivars();
+
+    tfree(errMsg);
+
+    destroy_const_plot();
+    spice_destroy_devices();
+    unset_all();
+    cp_resetcontrol(FALSE);
+    sh_delete_myvec();
+
+    return 0;
+};