diff --git a/acc_user.h b/acc_user.h
index 0b2bd7a97..abbbdbb5f 100644
--- a/acc_user.h
+++ b/acc_user.h
@@ -229,7 +229,7 @@ extern PLI_INT32 acc_fetch_size(handle obj);
 extern PLI_INT32 acc_fetch_type(handle obj);
 extern PLI_INT32 acc_fetch_fulltype(handle obj);
 extern PLI_INT32 acc_fetch_range(handle object, int *msb, int *lsb);
-extern char*     acc_fetch_type_str(PLI_INT32 type);
+extern const char* acc_fetch_type_str(PLI_INT32 type);
 
 extern char* acc_fetch_value(handle obj, const char*fmt, s_acc_value*value);
 
diff --git a/libveriuser/a_fetch_type_str.c b/libveriuser/a_fetch_type_str.c
index 6b8b5464b..403aa6dbe 100644
--- a/libveriuser/a_fetch_type_str.c
+++ b/libveriuser/a_fetch_type_str.c
@@ -22,7 +22,7 @@
 #include  <acc_user.h>
 
 
-char* acc_fetch_type_str(PLI_INT32 type)
+const char* acc_fetch_type_str(PLI_INT32 type)
 {
       switch (type) {
 	  case accNet:
diff --git a/vpi/sys_display.c b/vpi/sys_display.c
index fd0cc1b4b..2ea8e830f 100644
--- a/vpi/sys_display.c
+++ b/vpi/sys_display.c
@@ -50,7 +50,7 @@ static PLI_INT32 my_mcd_printf(PLI_UINT32 mcd, const char *fmt, ...)
 struct timeformat_info_s timeformat_info = { 0, 0, 0, 20 };
 
 struct strobe_cb_info {
-      char*name;
+      const char*name;
       char*filename;
       int lineno;
       int default_format;
@@ -129,7 +129,7 @@ static void array_from_iterator(struct strobe_cb_info*info, vpiHandle argv)
       }
 }
 
-static int get_default_format(char *name)
+static int get_default_format(const char *name)
 {
     int default_format;
 
@@ -256,7 +256,7 @@ static void get_time_real(char *rtn, double value, int prec,
 
 static unsigned int get_format_char(char **rtn, int ljust, int plus,
                                     int ld_zero, int width, int prec,
-                                    char fmt, struct strobe_cb_info *info,
+                                    char fmt, const struct strobe_cb_info *info,
                                     unsigned int *idx)
 {
   s_vpi_value value;
@@ -804,7 +804,7 @@ static unsigned int get_format_char(char **rtn, int ljust, int plus,
 /* We can't use the normal str functions on the return value since
  * %u and %z can insert NULL characters into the stream. */
 static unsigned int get_format(char **rtn, char *fmt,
-                               struct strobe_cb_info *info, unsigned int *idx)
+                               const struct strobe_cb_info *info, unsigned int *idx)
 {
   char *cp = fmt;
   unsigned int size;
@@ -851,7 +851,7 @@ static unsigned int get_format(char **rtn, char *fmt,
   return size - 1;
 }
 
-static unsigned int get_numeric(char **rtn, struct strobe_cb_info *info,
+static unsigned int get_numeric(char **rtn, const struct strobe_cb_info *info,
                                 vpiHandle item)
 {
   int size;
@@ -875,7 +875,7 @@ static unsigned int get_numeric(char **rtn, struct strobe_cb_info *info,
 
 /* In many places we can't use the normal str functions since %u and %z
  * can insert NULL characters into the stream. */
-static char *get_display(unsigned int *rtnsz, struct strobe_cb_info *info)
+static char *get_display(unsigned int *rtnsz, const struct strobe_cb_info *info)
 {
   char *result, *fmt, *rtn, *func_name;
   const char *cresult;
@@ -1012,7 +1012,7 @@ static char *get_display(unsigned int *rtnsz, struct strobe_cb_info *info)
   return rtn;
 }
 
-static int sys_check_args(vpiHandle callh, vpiHandle argv, PLI_BYTE8*name,
+static int sys_check_args(vpiHandle callh, vpiHandle argv, const PLI_BYTE8*name,
                           int no_auto, int is_monitor)
 {
       vpiHandle arg;
diff --git a/vpi/sys_fileio.c b/vpi/sys_fileio.c
index c1063c095..f3c1da5d8 100644
--- a/vpi/sys_fileio.c
+++ b/vpi/sys_fileio.c
@@ -182,7 +182,8 @@ static PLI_INT32 sys_fopenrwa_calltf(ICARUS_VPI_CONST PLI_BYTE8*name)
       vpiHandle callh = vpi_handle(vpiSysTfCall, 0);
       vpiHandle argv = vpi_iterate(vpiArgument, callh);
       s_vpi_value val;
-      char *mode, *fname;
+      char *fname;
+      const char *mode;
       errno = 0;
 
 	/* Get the mode. */
diff --git a/vpi/sys_finish.c b/vpi/sys_finish.c
index 077de849e..56489c05a 100644
--- a/vpi/sys_finish.c
+++ b/vpi/sys_finish.c
@@ -37,7 +37,7 @@ static PLI_INT32 sys_finish_calltf(ICARUS_VPI_CONST PLI_BYTE8 *name)
             diag_msg = val.value.integer;
       }
 
-      if (strcmp((char*)name, "$stop") == 0) {
+      if (strcmp((const char*)name, "$stop") == 0) {
 	    vpi_control(vpiStop, diag_msg);
 	    return 0;
       }
diff --git a/vpi/sys_priv.c b/vpi/sys_priv.c
index 131f3a060..55a6d076a 100644
--- a/vpi/sys_priv.c
+++ b/vpi/sys_priv.c
@@ -60,7 +60,7 @@ char *as_escaped(char *arg)
  * The result is duplicated so call free when the name is no
  * longer needed. Returns 0 (NULL) for an error.
  */
-char *get_filename(vpiHandle callh, char *name, vpiHandle file)
+char *get_filename(vpiHandle callh, const char *name, vpiHandle file)
 {
       s_vpi_value val;
       unsigned len, idx;
@@ -101,7 +101,7 @@ char *get_filename(vpiHandle callh, char *name, vpiHandle file)
       return strdup(val.value.str);
 }
 
-void check_for_extra_args(vpiHandle argv, vpiHandle callh, char *name,
+void check_for_extra_args(vpiHandle argv, vpiHandle callh, const char *name,
                           const char *arg_str, unsigned opt)
 {
 	/* Check that there are no extra arguments. */
diff --git a/vpi/sys_priv.h b/vpi/sys_priv.h
index d501040a5..094416f28 100644
--- a/vpi/sys_priv.h
+++ b/vpi/sys_priv.h
@@ -36,9 +36,9 @@ extern unsigned long genrand(struct context_s *context);
 extern PLI_UINT64 timerec_to_time64(const struct t_vpi_time*timerec);
 
 extern char *as_escaped(char *arg);
-extern char *get_filename(vpiHandle callh, char *name, vpiHandle file);
+extern char *get_filename(vpiHandle callh, const char *name, vpiHandle file);
 
-extern void check_for_extra_args(vpiHandle argv, vpiHandle callh, char *name,
+extern void check_for_extra_args(vpiHandle argv, vpiHandle callh, const char *name,
                                  const char *arg_str, unsigned opt);
 
 struct timeformat_info_s {
diff --git a/vpi/sys_random.c b/vpi/sys_random.c
index 8fc343fba..67d10ad9a 100644
--- a/vpi/sys_random.c
+++ b/vpi/sys_random.c
@@ -365,7 +365,7 @@ static double erlangian(long *seed, long k, long mean)
 }
 
 /* A seed can only be an integer/time variable or a register. */
-static unsigned is_seed_obj(vpiHandle obj, vpiHandle callh, char *name)
+static unsigned is_seed_obj(vpiHandle obj, vpiHandle callh, const char *name)
 {
       unsigned rtn = 0;
 
diff --git a/vpi/sys_readmem.c b/vpi/sys_readmem.c
index 309e73d31..fc729c0e0 100644
--- a/vpi/sys_readmem.c
+++ b/vpi/sys_readmem.c
@@ -29,7 +29,7 @@
 char **search_list = NULL;
 unsigned sl_count = 0;
 
-static void get_mem_params(vpiHandle argv, vpiHandle callh, char *name,
+static void get_mem_params(vpiHandle argv, vpiHandle callh, const char *name,
                            char **fname, vpiHandle *mitem,
                            vpiHandle *start_item, vpiHandle *stop_item)
 {
@@ -82,7 +82,7 @@ static void get_mem_params(vpiHandle argv, vpiHandle callh, char *name,
 
 static int process_params(vpiHandle mitem,
                           vpiHandle start_item, vpiHandle stop_item,
-                          vpiHandle callh, char *name,
+                          vpiHandle callh, const char *name,
                           int *start_addr, int *stop_addr, int *addr_incr,
                           int *min_addr, int *max_addr)
 {
diff --git a/vpi/sys_scanf.c b/vpi/sys_scanf.c
index 220ebfe43..e40362641 100644
--- a/vpi/sys_scanf.c
+++ b/vpi/sys_scanf.c
@@ -561,7 +561,7 @@ static int is_assignable_obj(vpiHandle obj)
       return rtn;
 }
 
-static int sys_check_args(vpiHandle callh, vpiHandle argv, PLI_BYTE8 *name)
+static int sys_check_args(vpiHandle callh, vpiHandle argv, const PLI_BYTE8 *name)
 {
       vpiHandle arg;
       int cnt = 3, rtn = 0;
diff --git a/vpi/v2005_math.c b/vpi/v2005_math.c
index e37853bcd..057252b43 100644
--- a/vpi/v2005_math.c
+++ b/vpi/v2005_math.c
@@ -162,7 +162,7 @@ vpiHandle va_process_argument(vpiHandle callh, const char *name,
 static PLI_INT32 va_single_argument_compiletf(ICARUS_VPI_CONST PLI_BYTE8 *ud)
 {
     vpiHandle callh, argv, arg;
-    t_single_data *data;
+    const t_single_data *data;
     const char *name;
     va_single_t* fun_data;
 
@@ -170,7 +170,7 @@ static PLI_INT32 va_single_argument_compiletf(ICARUS_VPI_CONST PLI_BYTE8 *ud)
     callh = vpi_handle(vpiSysTfCall, 0);
     assert(callh != 0);
     argv = vpi_iterate(vpiArgument, callh);
-    data = (t_single_data *) ud;
+    data = (const t_single_data *) ud;
     name = data->name;
 
     fun_data = malloc(sizeof(va_single_t));
@@ -244,7 +244,7 @@ static PLI_INT32 va_single_argument_calltf(ICARUS_VPI_CONST PLI_BYTE8 *ud)
 static PLI_INT32 va_double_argument_compiletf(ICARUS_VPI_CONST PLI_BYTE8 *ud)
 {
     vpiHandle callh, argv, arg;
-    t_double_data *data;
+    const t_double_data *data;
     const char *name;
     va_double_t* fun_data;
 
@@ -252,7 +252,7 @@ static PLI_INT32 va_double_argument_compiletf(ICARUS_VPI_CONST PLI_BYTE8 *ud)
     callh = vpi_handle(vpiSysTfCall, 0);
     assert(callh != 0);
     argv = vpi_iterate(vpiArgument, callh);
-    data = (t_double_data *) ud;
+    data = (const t_double_data *) ud;
     name = data->name;
 
     fun_data = malloc(sizeof(va_double_t));
diff --git a/vpi/va_math.c b/vpi/va_math.c
index 40f2b3196..51b30c1cc 100644
--- a/vpi/va_math.c
+++ b/vpi/va_math.c
@@ -189,7 +189,7 @@ vpiHandle va_process_argument(vpiHandle callh, const char *name,
 static PLI_INT32 va_single_argument_compiletf(ICARUS_VPI_CONST PLI_BYTE8 *ud)
 {
     vpiHandle callh, argv, arg;
-    t_single_data *data;
+    const t_single_data *data;
     const char *name;
     va_single_t* fun_data;
 
@@ -197,7 +197,7 @@ static PLI_INT32 va_single_argument_compiletf(ICARUS_VPI_CONST PLI_BYTE8 *ud)
     callh = vpi_handle(vpiSysTfCall, 0);
     assert(callh != 0);
     argv = vpi_iterate(vpiArgument, callh);
-    data = (t_single_data *) ud;
+    data = (const t_single_data *) ud;
     name = data->name;
 
     fun_data = malloc(sizeof(va_single_t));
@@ -271,7 +271,7 @@ static PLI_INT32 va_single_argument_calltf(ICARUS_VPI_CONST PLI_BYTE8 *ud)
 static PLI_INT32 va_double_argument_compiletf(ICARUS_VPI_CONST PLI_BYTE8 *ud)
 {
     vpiHandle callh, argv, arg;
-    t_double_data *data;
+    const t_double_data *data;
     const char *name;
     va_double_t* fun_data;
 
@@ -279,7 +279,7 @@ static PLI_INT32 va_double_argument_compiletf(ICARUS_VPI_CONST PLI_BYTE8 *ud)
     callh = vpi_handle(vpiSysTfCall, 0);
     assert(callh != 0);
     argv = vpi_iterate(vpiArgument, callh);
-    data = (t_double_data *) ud;
+    data = (const t_double_data *) ud;
     name = data->name;
 
     fun_data = malloc(sizeof(va_double_t));
diff --git a/vpi/vcd_priv.c b/vpi/vcd_priv.c
index 9a900294c..9fe8c0904 100644
--- a/vpi/vcd_priv.c
+++ b/vpi/vcd_priv.c
@@ -80,8 +80,8 @@ void vcd_names_delete(struct vcd_names_list_s*tab)
 
 static int vcd_names_compare(const void *s1, const void *s2)
 {
-      const char *v1 = *(const char **) s1;
-      const char *v2 = *(const char **) s2;
+      const char *v1 = *(const char * const *) s1;
+      const char *v2 = *(const char * const *) s2;
 
       return strcmp(v1, v2);
 }