diff --git a/src/regparse.c b/src/regparse.c
index 24bcbaac..9acdd6e2 100644
--- a/src/regparse.c
+++ b/src/regparse.c
@@ -793,8 +793,13 @@ onig_print_names(FILE* fp, regex_t* reg)
 #endif /* ONIG_DEBUG */
 
 static int
-i_free_name_entry(UChar* key, NameEntry* e, void* arg ARG_UNUSED)
+i_free_name_entry(st_data_t akey, st_data_t ae, st_data_t arg ARG_UNUSED)
 {
+  UChar* key;
+  NameEntry* e;
+
+  key = (UChar* )akey;
+  e = (NameEntry* )ae;
   xfree(e->name);
   if (IS_NOT_NULL(e->back_refs)) xfree(e->back_refs);
   xfree(key);
@@ -850,8 +855,14 @@ typedef struct {
 } INamesArg;
 
 static int
-i_names(UChar* key ARG_UNUSED, NameEntry* e, INamesArg* arg)
+i_names(st_data_t key ARG_UNUSED, st_data_t ae, st_data_t aarg)
 {
+  NameEntry* e;
+  INamesArg* arg;
+
+  e = (NameEntry* )ae;
+  arg = (INamesArg* )aarg;
+
   int r = (*(arg->func))(e->name,
                          e->name + e->name_len,
                          e->back_num,
@@ -883,9 +894,14 @@ onig_foreach_name(regex_t* reg,
 }
 
 static int
-i_renumber_name(UChar* key ARG_UNUSED, NameEntry* e, GroupNumMap* map)
+i_renumber_name(st_data_t key ARG_UNUSED, st_data_t ae, st_data_t amap)
 {
   int i;
+  NameEntry* e;
+  GroupNumMap* map;
+
+  e = (NameEntry* )ae;
+  map = (GroupNumMap* )amap;
 
   if (e->back_num > 1) {
     for (i = 0; i < e->back_num; i++) {
@@ -1374,9 +1390,14 @@ static int CalloutNameIDCounter;
 #ifdef USE_ST_LIBRARY
 
 static int
-i_free_callout_name_entry(st_callout_name_key* key, CalloutNameEntry* e,
-                          void* arg ARG_UNUSED)
+i_free_callout_name_entry(st_data_t akey, st_data_t ae, st_data_t arg ARG_UNUSED)
 {
+  st_callout_name_key* key;
+  CalloutNameEntry* e;
+
+  key = (st_callout_name_key* )akey;
+  e = (CalloutNameEntry* )ae;
+
   if (IS_NOT_NULL(e)) {
     xfree(e->name);
   }
@@ -1870,10 +1891,14 @@ typedef intptr_t   CalloutTagVal;
 #define CALLOUT_TAG_LIST_FLAG_TAG_EXIST     (1<<0)
 
 static int
-i_callout_callout_list_set(UChar* key, CalloutTagVal e, void* arg)
+i_callout_callout_list_set(st_data_t key ARG_UNUSED, st_data_t ae, st_data_t arg)
 {
   int num;
-  RegexExt* ext = (RegexExt* )arg;
+  CalloutTagVal e;
+  RegexExt* ext;
+
+  e   = (CalloutTagVal )ae;
+  ext = (RegexExt* )arg;
 
   num = (int )e - 1;
   ext->callout_list[num].flag |= CALLOUT_TAG_LIST_FLAG_TAG_EXIST;
@@ -1926,8 +1951,11 @@ onig_callout_tag_is_exist_at_callout_num(regex_t* reg, int callout_num)
 }
 
 static int
-i_free_callout_tag_entry(UChar* key, CalloutTagVal e, void* arg ARG_UNUSED)
+i_free_callout_tag_entry(st_data_t akey, st_data_t e ARG_UNUSED, st_data_t arg ARG_UNUSED)
 {
+  UChar* key;
+
+  key = (UChar* )akey;
   xfree(key);
   return ST_DELETE;
 }
diff --git a/src/st.h b/src/st.h
index 5efee8bb..70798dc5 100644
--- a/src/st.h
+++ b/src/st.h
@@ -34,13 +34,6 @@ enum st_retval {ST_CONTINUE, ST_STOP, ST_DELETE, ST_CHECK};
 #ifndef _
 # define _(args) args
 #endif
-#ifndef ANYARGS
-# ifdef __cplusplus
-#   define ANYARGS ...
-# else
-#   define ANYARGS
-# endif
-#endif
 
 st_table *st_init_table _((struct st_hash_type *));
 st_table *st_init_table_with_size _((struct st_hash_type *, int));
@@ -52,7 +45,7 @@ int st_delete _((st_table *, st_data_t *, st_data_t *));
 int st_delete_safe _((st_table *, st_data_t *, st_data_t *, st_data_t));
 int st_insert _((st_table *, st_data_t, st_data_t));
 int st_lookup _((st_table *, st_data_t, st_data_t *));
-int st_foreach _((st_table *, int (*)(ANYARGS), st_data_t));
+int st_foreach _((st_table *, int (*)(st_data_t, st_data_t, st_data_t), st_data_t));
 void st_add_direct _((st_table *, st_data_t, st_data_t));
 void st_free_table _((st_table *));
 void st_cleanup_safe _((st_table *, st_data_t));