Add function ngSpice_nospiceinit(void) if you don't want to read .spiceinit

src/include/ngspice/sharedspice.h

@@ -3,12 +3,21 @@
 /* Modified BSD license */
 
 /*
-Interface between a calling program (caller) and ngspice.dll (ngspice.so)
+Interface between a calling program (caller) and ngspice.dll (libngspice.so)
+
 **
 ngSpice_nospinit(void)
 Set variable no_spinit, if reading the initialization file 'spinit' is not wanted.
 To be called before ngSpice_Init()
 
+**
+ngSpice_nospiceinit(void)
+Set variable no_spiceinit, if reading the user defined initialization file 
+'.spiceinit' is not wanted.
+To be called before ngSpice_Init().
+Use with care, as this removes the last chance to send preparative commands
+before the netlist is loaded. Then use the the caller to send such commands.
+
 **
 ngSpice_Init(SendChar*, SendStat*, ControlledExit*,
              SendData*, SendInitData*, BGThreadRunning*, void*)
@@ -453,6 +462,10 @@ NG_BOOL ngSpice_SetBkpt(double time);
 IMPEXP
 int ngSpice_nospinit(void);
 
+/* Set variable no_spiceinit, if reading '.spiceinit' is not wanted. */
+IMPEXP
+int ngSpice_nospiceinit(void);
+
 #ifdef __cplusplus
 }
 #endif

src/sharedspice.c

@@ -814,6 +814,16 @@ ngSpice_nospinit(void)
     return 0;
 }
 
+/* Set variable no_spiceinit, if reading '.spiceinit' is not wanted. */
+IMPEXP
+int
+ngSpice_nospiceinit(void)
+{
+    bool t = TRUE;
+    cp_vset("no_spicenit", CP_BOOL, &t);
+    return 0;
+}
+
 /* Initialise external voltage source and synchronization */
 IMPEXP
 int
@@ -972,7 +982,9 @@ ngSpice_Init(SendChar* printfcn, SendStat* statusfcn, ControlledExit* ngspiceexi
        try accessing the initialisation file .spiceinit in a user provided
        path read from environmental variable SPICE_USERINIT_DIR, 
        if that fails try the alternate name spice.rc, then look into
-               the current directory, then the HOME directory, then into USERPROFILE */
+       the current directory, then the HOME directory, then into USERPROFILE.
+       Don't read .spiceinit, if ngSpice_nospiceinit() has been called. */
+    if (!cp_getvar("no_spiceinit", CP_BOOL, NULL, 0)) {
         do {
             {
                 const char* const userinit = getenv("SPICE_USERINIT_DIR");
@@ -1017,6 +1029,10 @@ ngSpice_Init(SendChar* printfcn, SendStat* statusfcn, ControlledExit* ngspiceexi
                 }
             }
         } while (0); /* end of case that init file is read */
+    }
+    else {
+        fprintf(stdout, "Note: .spiceinit is ignored, because ngSpice_nospiceinit() has been called.\n");
+    }
 
 #endif /* ~ HAVE_PWD_H */