diff --git a/quickjs-libc.c b/quickjs-libc.c
index b59c6ac..2b26e85 100644
--- a/quickjs-libc.c
+++ b/quickjs-libc.c
@@ -160,6 +160,7 @@ static BOOL my_isdigit(int c)
     return (c >= '0' && c <= '9');
 }
 
+/* XXX: use 'o' and 'O' for object using JS_PrintValue() ? */
 static JSValue js_printf_internal(JSContext *ctx,
                                   int argc, JSValueConst *argv, FILE *fp)
 {
@@ -1083,10 +1084,16 @@ static JSValue js_std_file_printf(JSContext *ctx, JSValueConst this_val,
     return js_printf_internal(ctx, argc, argv, f);
 }
 
+static void js_print_value_write(void *opaque, const char *buf, size_t len)
+{
+    FILE *fo = opaque;
+    fwrite(buf, 1, len, fo);
+}
+
 static JSValue js_std_file_printObject(JSContext *ctx, JSValueConst this_val,
                                        int argc, JSValueConst *argv)
 {
-    JS_PrintValue(ctx, stdout, argv[0], NULL);
+    JS_PrintValue(ctx, js_print_value_write, stdout, argv[0], NULL);
     return JS_UNDEFINED;
 }
 
@@ -3914,7 +3921,7 @@ static JSValue js_print(JSContext *ctx, JSValueConst this_val,
             fwrite(str, 1, len, stdout);
             JS_FreeCString(ctx, str);
         } else {
-            JS_PrintValue(ctx, stdout, v, NULL);
+            JS_PrintValue(ctx, js_print_value_write, stdout, v, NULL);
         }
     }
     putchar('\n');
@@ -4028,7 +4035,7 @@ void js_std_free_handlers(JSRuntime *rt)
 
 static void js_std_dump_error1(JSContext *ctx, JSValueConst exception_val)
 {
-    JS_PrintValue(ctx, stderr, exception_val, NULL);
+    JS_PrintValue(ctx, js_print_value_write, stderr, exception_val, NULL);
     fputc('\n', stderr);
 }
 
diff --git a/quickjs.c b/quickjs.c
index a73485c..a39a474 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -1078,7 +1078,6 @@ static __exception int JS_ToArrayLengthFree(JSContext *ctx, uint32_t *plen,
 static JSValue JS_EvalObject(JSContext *ctx, JSValueConst this_obj,
                              JSValueConst val, int flags, int scope_idx);
 JSValue __attribute__((format(printf, 2, 3))) JS_ThrowInternalError(JSContext *ctx, const char *fmt, ...);
-static void js_print_atom(JSRuntime *rt, FILE *fo, JSAtom atom);
 static __maybe_unused void JS_DumpAtoms(JSRuntime *rt);
 static __maybe_unused void JS_DumpString(JSRuntime *rt, const JSString *p);
 static __maybe_unused void JS_DumpObjectHeader(JSRuntime *rt);
@@ -1087,6 +1086,7 @@ static __maybe_unused void JS_DumpGCObject(JSRuntime *rt, JSGCObjectHeader *p);
 static __maybe_unused void JS_DumpValueRT(JSRuntime *rt, const char *str, JSValueConst val);
 static __maybe_unused void JS_DumpValue(JSContext *ctx, const char *str, JSValueConst val);
 static __maybe_unused void JS_DumpShapes(JSRuntime *rt);
+static void js_dump_value_write(void *opaque, const char *buf, size_t len);
 static JSValue js_function_apply(JSContext *ctx, JSValueConst this_val,
                                  int argc, JSValueConst *argv, int magic);
 static void js_array_finalizer(JSRuntime *rt, JSValue val);
@@ -3201,11 +3201,6 @@ static BOOL JS_AtomSymbolHasDescription(JSContext *ctx, JSAtom v)
             !(p->len == 0 && p->is_wide_char != 0));
 }
 
-static __maybe_unused void print_atom(JSContext *ctx, JSAtom atom)
-{
-    js_print_atom(ctx->rt, stdout, atom);
-}
-
 /* free with JS_FreeCString() */
 const char *JS_AtomToCString(JSContext *ctx, JSAtom atom)
 {
@@ -12962,20 +12957,42 @@ typedef struct {
     JSRuntime *rt;
     JSContext *ctx; /* may be NULL */
     JSPrintValueOptions options;
-    FILE *fo;
+    JSPrintValueWrite *write_func;
+    void *write_opaque;
     int level;
     JSObject *print_stack[JS_PRINT_MAX_DEPTH]; /* level values */
 } JSPrintValueState;
 
 static void js_print_value(JSPrintValueState *s, JSValueConst val);
 
+static void js_putc(JSPrintValueState *s, char c)
+{
+    s->write_func(s->write_opaque, &c, 1);
+}
+
+static void js_puts(JSPrintValueState *s, const char *str)
+{
+    s->write_func(s->write_opaque, str, strlen(str));
+}
+
+static void __attribute__((format(printf, 2, 3))) js_printf(JSPrintValueState *s, const char *fmt, ...)
+{
+    va_list ap;
+    char buf[256];
+    
+    va_start(ap, fmt);
+    vsnprintf(buf, sizeof(buf), fmt, ap);
+    va_end(ap);
+    s->write_func(s->write_opaque, buf, strlen(buf));
+}
+
 static void js_print_float64(JSPrintValueState *s, double d)
 {
     JSDTOATempMem dtoa_mem;
     char buf[32];
     int len;
     len = js_dtoa(buf, d, 10, 0, JS_DTOA_FORMAT_FREE | JS_DTOA_MINUS_ZERO, &dtoa_mem);
-    fwrite(buf, 1, len, s->fo);
+    s->write_func(s->write_opaque, buf, len);
 }
 
 static uint32_t js_string_get_length(JSValueConst val)
@@ -12991,8 +13008,23 @@ static uint32_t js_string_get_length(JSValueConst val)
     }
 }
 
+static void js_dump_char(JSPrintValueState *s, int c, int sep)
+{
+    if (c == sep || c == '\\') {
+        js_putc(s, '\\');
+        js_putc(s, c);
+    } else if (c >= ' ' && c <= 126) {
+        js_putc(s, c);
+    } else if (c == '\n') {
+        js_putc(s, '\\');
+        js_putc(s, 'n');
+    } else {
+        js_printf(s, "\\u%04x", c);
+    }
+}
+
 static void js_print_string_rec(JSPrintValueState *s, JSValueConst val,
-                                    int sep, uint32_t pos)
+                                int sep, uint32_t pos)
 {
     if (JS_VALUE_GET_TAG(val) == JS_TAG_STRING) {
         JSString *p = JS_VALUE_GET_STRING(val);
@@ -13000,7 +13032,7 @@ static void js_print_string_rec(JSPrintValueState *s, JSValueConst val,
         if (pos < s->options.max_string_length) {
             len = min_uint32(p->len, s->options.max_string_length - pos);
             for(i = 0; i < len; i++) {
-                JS_DumpChar(s->fo, string_get(p, i), sep);
+                js_dump_char(s, string_get(p, i), sep);
             }
         }
     } else if (JS_VALUE_GET_TAG(val) == JS_TAG_STRING_ROPE) {
@@ -13008,7 +13040,7 @@ static void js_print_string_rec(JSPrintValueState *s, JSValueConst val,
         js_print_string_rec(s, r->left, sep, pos);
         js_print_string_rec(s, r->right, sep, pos + js_string_get_length(r->left));
     } else {
-        fprintf(s->fo, "<invalid string tag %d>", (int)JS_VALUE_GET_TAG(val));
+        js_printf(s, "<invalid string tag %d>", (int)JS_VALUE_GET_TAG(val));
     }
 }
 
@@ -13017,17 +13049,17 @@ static void js_print_string(JSPrintValueState *s, JSValueConst val)
     int sep;
     if (s->options.raw_dump && JS_VALUE_GET_TAG(val) == JS_TAG_STRING) {
         JSString *p = JS_VALUE_GET_STRING(val);
-        fprintf(s->fo, "%d", p->header.ref_count);
+        js_printf(s, "%d", p->header.ref_count);
         sep = (p->header.ref_count == 1) ? '\"' : '\'';
     } else {
         sep = '\"';
     }
-    fputc(sep, s->fo);
+    js_putc(s, sep);
     js_print_string_rec(s, val, sep, 0);
-    fputc(sep, s->fo);
+    js_putc(s, sep);
     if (js_string_get_length(val) > s->options.max_string_length) {
         uint32_t n = js_string_get_length(val) - s->options.max_string_length;
-        fprintf(s->fo, "... %u more character%s", n, n > 1 ? "s" : "");
+        js_printf(s, "... %u more character%s", n, n > 1 ? "s" : "");
     }
 }
 
@@ -13039,7 +13071,7 @@ static void js_print_raw_string2(JSPrintValueState *s, JSValueConst val, BOOL re
     if (cstr) {
         if (remove_last_lf && len > 0 && cstr[len - 1] == '\n')
             len--;
-        fwrite(cstr, 1, len, s->fo);
+        s->write_func(s->write_opaque, cstr, len);
         JS_FreeCString(s->ctx, cstr);
     }
 }
@@ -13064,27 +13096,27 @@ static BOOL is_ascii_ident(const JSString *p)
     return TRUE;
 }
 
-static void js_print_atom(JSRuntime *rt, FILE *fo, JSAtom atom)
+static void js_print_atom(JSPrintValueState *s, JSAtom atom)
 {
     int i;
     if (__JS_AtomIsTaggedInt(atom)) {
-        fprintf(fo, "%u", __JS_AtomToUInt32(atom));
+        js_printf(s, "%u", __JS_AtomToUInt32(atom));
     } else if (atom == JS_ATOM_NULL) {
-        fprintf(fo, "<null>");
+        js_puts(s, "<null>");
     } else {
-        assert(atom < rt->atom_size);
+        assert(atom < s->rt->atom_size);
         JSString *p;
-        p = rt->atom_array[atom];
+        p = s->rt->atom_array[atom];
         if (is_ascii_ident(p)) {
             for(i = 0; i < p->len; i++) {
-                fputc(string_get(p, i), fo);
+                js_putc(s, string_get(p, i));
             }
         } else {
-            fputc('"', fo);
+            js_putc(s, '"');
             for(i = 0; i < p->len; i++) {
-                JS_DumpChar(fo, string_get(p, i), '\"');
+                js_dump_char(s, string_get(p, i), '\"');
             }
-            fputc('"', fo);
+            js_putc(s, '"');
         }
     }
 }
@@ -13118,10 +13150,10 @@ static void js_print_comma(JSPrintValueState *s, int *pcomma_state)
     case 0:
         break;
     case 1:
-        fprintf(s->fo, ", ");
+        js_printf(s, ", ");
         break;
     case 2:
-        fprintf(s->fo, " { ");
+        js_printf(s, " { ");
         break;
     }
     *pcomma_state = 1;
@@ -13131,7 +13163,7 @@ static void js_print_more_items(JSPrintValueState *s, int *pcomma_state,
                                 uint32_t n)
 {
     js_print_comma(s, pcomma_state);
-    fprintf(s->fo, "... %u more item%s", n, n > 1 ? "s" : "");
+    js_printf(s, "... %u more item%s", n, n > 1 ? "s" : "");
 }
 
 static void js_print_object(JSPrintValueState *s, JSObject *p)
@@ -13148,7 +13180,7 @@ static void js_print_object(JSPrintValueState *s, JSObject *p)
     is_array = FALSE;
     if (p->class_id == JS_CLASS_ARRAY) {
         is_array = TRUE;
-        fprintf(s->fo, "[ ");
+        js_printf(s, "[ ");
         /* XXX: print array like properties even if not fast array */
         if (p->fast_array) {
             uint32_t len, n, len1;
@@ -13164,7 +13196,7 @@ static void js_print_object(JSPrintValueState *s, JSObject *p)
             if (p->u.array.count < len) {
                 n = len - p->u.array.count;
                 js_print_comma(s, &comma_state);
-                fprintf(s->fo, "<%u empty item%s>", n, n > 1 ? "s" : "");
+                js_printf(s, "<%u empty item%s>", n, n > 1 ? "s" : "");
             }
         }
     } else if (p->class_id >= JS_CLASS_UINT8C_ARRAY && p->class_id <= JS_CLASS_FLOAT64_ARRAY) {
@@ -13172,8 +13204,8 @@ static void js_print_object(JSPrintValueState *s, JSObject *p)
         uint32_t len1;
         int64_t v;
 
-        js_print_atom(s->rt, s->fo, rt->class_array[p->class_id].class_name);
-        fprintf(s->fo, "(%u) [ ", p->u.array.count);
+        js_print_atom(s, rt->class_array[p->class_id].class_name);
+        js_printf(s, "(%u) [ ", p->u.array.count);
         
         is_array = TRUE;
         len1 = min_uint32(p->u.array.count, s->options.max_item_count);
@@ -13203,10 +13235,10 @@ static void js_print_object(JSPrintValueState *s, JSObject *p)
             case JS_CLASS_BIG_INT64_ARRAY:
                 v = *(int64_t *)ptr;
             ta_int64:
-                fprintf(s->fo, "%" PRId64, v);
+                js_printf(s, "%" PRId64, v);
                 break;
             case JS_CLASS_BIG_UINT64_ARRAY:
-                fprintf(s->fo, "%" PRIu64, *(uint64_t *)ptr);
+                js_printf(s, "%" PRIu64, *(uint64_t *)ptr);
                 break;
             case JS_CLASS_FLOAT32_ARRAY:
                 js_print_float64(s, *(float *)ptr);
@@ -13221,19 +13253,19 @@ static void js_print_object(JSPrintValueState *s, JSObject *p)
     } else if (p->class_id == JS_CLASS_BYTECODE_FUNCTION ||
                (rt->class_array[p->class_id].call != NULL &&
                 p->class_id != JS_CLASS_PROXY)) {
-        fprintf(s->fo, "[Function");
+        js_printf(s, "[Function");
         /* XXX: allow dump without ctx */
         if (!s->options.raw_dump && s->ctx) {
             const char *func_name_str;
-            fputc(' ', s->fo);
+            js_putc(s, ' ');
             func_name_str = get_func_name(s->ctx, JS_MKPTR(JS_TAG_OBJECT, p));
             if (!func_name_str || func_name_str[0] == '\0')
-                fputs("(anonymous)", s->fo);
+                js_puts(s, "(anonymous)");
             else
-                fputs(func_name_str, s->fo);
+                js_puts(s, func_name_str);
             JS_FreeCString(s->ctx, func_name_str);
         }
-        fprintf(s->fo, "]");
+        js_printf(s, "]");
         comma_state = 2;
     } else if (p->class_id == JS_CLASS_MAP || p->class_id == JS_CLASS_SET) {
         JSMapState *ms = p->u.opaque;
@@ -13241,8 +13273,8 @@ static void js_print_object(JSPrintValueState *s, JSObject *p)
         
         if (!ms)
             goto default_obj;
-        js_print_atom(s->rt, s->fo, rt->class_array[p->class_id].class_name);
-        fprintf(s->fo, "(%u) { ", ms->record_count);
+        js_print_atom(s, rt->class_array[p->class_id].class_name);
+        js_printf(s, "(%u) { ", ms->record_count);
         i = 0;
         list_for_each(el, &ms->records) {
             JSMapRecord *mr = list_entry(el, JSMapRecord, link);
@@ -13251,7 +13283,7 @@ static void js_print_object(JSPrintValueState *s, JSObject *p)
                 continue;
             js_print_value(s, mr->key);
             if (p->class_id == JS_CLASS_MAP) {
-                fprintf(s->fo, " => ");
+                js_printf(s, " => ");
                 js_print_value(s, mr->value);
             }
             i++;
@@ -13283,7 +13315,7 @@ static void js_print_object(JSPrintValueState *s, JSObject *p)
         /* dump the stack if present */
         str = JS_GetProperty(s->ctx, JS_MKPTR(JS_TAG_OBJECT, p), JS_ATOM_stack);
         if (JS_IsString(str)) {
-            fputc('\n', s->fo);
+            js_putc(s, '\n');
             /* XXX: should remove the last '\n' in stack as
                v8. SpiderMonkey does not do it */
             js_print_raw_string2(s, str, TRUE);
@@ -13293,10 +13325,10 @@ static void js_print_object(JSPrintValueState *s, JSObject *p)
     } else {
         default_obj:
         if (p->class_id != JS_CLASS_OBJECT) {
-            js_print_atom(s->rt, s->fo, rt->class_array[p->class_id].class_name);
-            fprintf(s->fo, " ");
+            js_print_atom(s, rt->class_array[p->class_id].class_name);
+            js_printf(s, " ");
         }
-        fprintf(s->fo, "{ ");
+        js_printf(s, "{ ");
     }
     
     sh = p->shape; /* the shape can be NULL while freeing an object */
@@ -13313,39 +13345,39 @@ static void js_print_object(JSPrintValueState *s, JSObject *p)
                 if (j < s->options.max_item_count) {
                     pr = &p->prop[i];
                     js_print_comma(s, &comma_state);
-                    js_print_atom(s->rt, s->fo, prs->atom);
-                    fprintf(s->fo, ": ");
+                    js_print_atom(s, prs->atom);
+                    js_printf(s, ": ");
                     
                     /* XXX: autoinit property */
                     if ((prs->flags & JS_PROP_TMASK) == JS_PROP_GETSET) {
                         if (s->options.raw_dump) {
-                            fprintf(s->fo, "[Getter %p Setter %p]",
+                            js_printf(s, "[Getter %p Setter %p]",
                                     pr->u.getset.getter, pr->u.getset.setter);
                         } else {
                             if (pr->u.getset.getter && pr->u.getset.setter) {
-                                fprintf(s->fo, "[Getter/Setter]");
+                                js_printf(s, "[Getter/Setter]");
                             } else if (pr->u.getset.setter) {
-                                fprintf(s->fo, "[Setter]");
+                                js_printf(s, "[Setter]");
                             } else {
-                                fprintf(s->fo, "[Getter]");
+                                js_printf(s, "[Getter]");
                             }
                         }
                     } else if ((prs->flags & JS_PROP_TMASK) == JS_PROP_VARREF) {
                         if (s->options.raw_dump) {
-                            fprintf(s->fo, "[varref %p]", (void *)pr->u.var_ref);
+                            js_printf(s, "[varref %p]", (void *)pr->u.var_ref);
                         } else {
                             js_print_value(s, *pr->u.var_ref->pvalue);
                         }
                     } else if ((prs->flags & JS_PROP_TMASK) == JS_PROP_AUTOINIT) {
                         if (s->options.raw_dump) {
-                            fprintf(s->fo, "[autoinit %p %d %p]",
+                            js_printf(s, "[autoinit %p %d %p]",
                                     (void *)js_autoinit_get_realm(pr),
                                     js_autoinit_get_id(pr),
                                     (void *)pr->u.init.opaque);
                         } else {
                             /* XXX: could autoinit but need to restart
                                the iteration */
-                            fprintf(s->fo, "[autoinit]");
+                            js_printf(s, "[autoinit]");
                         }
                     } else {
                         js_print_value(s, pr->u.value);
@@ -13357,34 +13389,34 @@ static void js_print_object(JSPrintValueState *s, JSObject *p)
         if (j > s->options.max_item_count)
             js_print_more_items(s, &comma_state, j - s->options.max_item_count);
     }
-    if (s->options.show_closure && js_class_has_bytecode(p->class_id)) {
+    if (s->options.raw_dump && js_class_has_bytecode(p->class_id)) {
         JSFunctionBytecode *b = p->u.func.function_bytecode;
         if (b->closure_var_count) {
             JSVarRef **var_refs;
             var_refs = p->u.func.var_refs;
             
             js_print_comma(s, &comma_state);
-            fprintf(s->fo, "[[Closure]]: [");
+            js_printf(s, "[[Closure]]: [");
             for(i = 0; i < b->closure_var_count; i++) {
                 if (i != 0)
-                    fprintf(s->fo, ", ");
+                    js_printf(s, ", ");
                 js_print_value(s, var_refs[i]->value);
             }
-            fprintf(s->fo, " ]");
+            js_printf(s, " ]");
         }
         if (p->u.func.home_object) {
             js_print_comma(s, &comma_state);
-            fprintf(s->fo, "[[HomeObject]]: ");
+            js_printf(s, "[[HomeObject]]: ");
             js_print_value(s, JS_MKPTR(JS_TAG_OBJECT, p->u.func.home_object));
         }
     }
 
     if (!is_array) {
         if (comma_state != 2) {
-            fprintf(s->fo, " }");
+            js_printf(s, " }");
         }
     } else {
-        fprintf(s->fo, " ]");
+        js_printf(s, " ]");
     }
 }
 
@@ -13404,7 +13436,7 @@ static void js_print_value(JSPrintValueState *s, JSValueConst val)
 
     switch(tag) {
     case JS_TAG_INT:
-        fprintf(s->fo, "%d", JS_VALUE_GET_INT(val));
+        js_printf(s, "%d", JS_VALUE_GET_INT(val));
         break;
     case JS_TAG_BOOL:
         if (JS_VALUE_GET_BOOL(val))
@@ -13424,13 +13456,13 @@ static void js_print_value(JSPrintValueState *s, JSValueConst val)
     case JS_TAG_UNDEFINED:
         str = "undefined";
     print_str:
-        fprintf(s->fo, "%s", str);
+        js_puts(s, str);
         break;
     case JS_TAG_FLOAT64:
         js_print_float64(s, JS_VALUE_GET_FLOAT64(val));
         break;
     case JS_TAG_SHORT_BIG_INT:
-        fprintf(s->fo, "%" PRId64 "n", (int64_t)JS_VALUE_GET_SHORT_BIG_INT(val));
+        js_printf(s, "%" PRId64 "n", (int64_t)JS_VALUE_GET_SHORT_BIG_INT(val));
         break;
     case JS_TAG_BIG_INT:
         if (!s->options.raw_dump && s->ctx) {
@@ -13438,7 +13470,7 @@ static void js_print_value(JSPrintValueState *s, JSValueConst val)
             if (JS_IsException(str))
                 goto raw_bigint;
             js_print_raw_string(s, str);
-            fputc('n', s->fo);
+            js_putc(s, 'n');
             JS_FreeValueRT(s->rt, str);
         } else {
             JSBigInt *p;
@@ -13448,27 +13480,27 @@ static void js_print_value(JSPrintValueState *s, JSValueConst val)
             /* In order to avoid allocations we just dump the limbs */
             sgn = js_bigint_sign(p);
             if (sgn)
-                fprintf(s->fo, "BigInt.asIntN(%d,", p->len * JS_LIMB_BITS);
-            fprintf(s->fo, "0x");
+                js_printf(s, "BigInt.asIntN(%d,", p->len * JS_LIMB_BITS);
+            js_printf(s, "0x");
             for(i = p->len - 1; i >= 0; i--) {
                 if (i != p->len - 1)
-                    fprintf(s->fo, "_");
+                    js_putc(s, '_');
 #if JS_LIMB_BITS == 32
-                fprintf(s->fo, "%08x", p->tab[i]);
+                js_printf(s, "%08x", p->tab[i]);
 #else
-                fprintf(s->fo, "%016" PRIx64, p->tab[i]);
+                js_printf(s, "%016" PRIx64, p->tab[i]);
 #endif
             }
-            fprintf(s->fo, "n");
+            js_putc(s, 'n');
             if (sgn)
-                fprintf(s->fo, ")");
+                js_putc(s, ')');
         }
         break;
     case JS_TAG_STRING:
     case JS_TAG_STRING_ROPE:
         if (s->options.raw_dump && tag == JS_TAG_STRING_ROPE) {
             JSStringRope *r = JS_VALUE_GET_STRING_ROPE(val);
-            fprintf(s->fo, "[rope len=%d depth=%d]", r->len, r->depth);
+            js_printf(s, "[rope len=%d depth=%d]", r->len, r->depth);
         } else {
             js_print_string(s, val);
         }
@@ -13476,9 +13508,9 @@ static void js_print_value(JSPrintValueState *s, JSValueConst val)
     case JS_TAG_FUNCTION_BYTECODE:
         {
             JSFunctionBytecode *b = JS_VALUE_GET_PTR(val);
-            fprintf(s->fo, "[bytecode ");
-            js_print_atom(s->rt, s->fo, b->func_name);
-            fprintf(s->fo, "]");
+            js_puts(s, "[bytecode ");
+            js_print_atom(s, b->func_name);
+            js_putc(s, ']');
         }
         break;
     case JS_TAG_OBJECT:
@@ -13487,35 +13519,35 @@ static void js_print_value(JSPrintValueState *s, JSValueConst val)
             int idx;
             idx = js_print_stack_index(s, p);
             if (idx >= 0) {
-                fprintf(s->fo, "[circular %d]", idx);
+                js_printf(s, "[circular %d]", idx);
             } else if (s->level < s->options.max_depth) {
                 s->print_stack[s->level++] = p;
                 js_print_object(s, JS_VALUE_GET_OBJ(val));
                 s->level--;
             } else {
                 JSAtom atom = s->rt->class_array[p->class_id].class_name;
-                fprintf(s->fo, "[");
-                js_print_atom(s->rt, s->fo, atom);
+                js_putc(s, '[');
+                js_print_atom(s, atom);
                 if (s->options.raw_dump) {
-                    fprintf(s->fo, " %p", (void *)p);
+                    js_printf(s, " %p", (void *)p);
                 }
-                fprintf(s->fo, "]");
+                js_putc(s, ']');
             }
         }
         break;
     case JS_TAG_SYMBOL:
         {
             JSAtomStruct *p = JS_VALUE_GET_PTR(val);
-            fprintf(s->fo, "Symbol(");
-            js_print_atom(s->rt, s->fo, js_get_atom_index(s->rt, p));
-            fprintf(s->fo, ")");
+            js_puts(s, "Symbol(");
+            js_print_atom(s, js_get_atom_index(s->rt, p));
+            js_putc(s, ')');
         }
         break;
     case JS_TAG_MODULE:
-        fprintf(s->fo, "[module]");
+        js_puts(s, "[module]");
         break;
     default:
-        fprintf(s->fo, "[unknown tag %d]", tag);
+        js_printf(s, "[unknown tag %d]", tag);
         break;
     }
 }
@@ -13528,8 +13560,9 @@ void JS_PrintValueSetDefaultOptions(JSPrintValueOptions *options)
     options->max_item_count = 100;
 }
 
-static void JS_PrintValueInternal(JSRuntime *rt, JSContext *ctx,
-                                  FILE *fo, JSValueConst val, const JSPrintValueOptions *options)
+static void JS_PrintValueInternal(JSRuntime *rt, JSContext *ctx, 
+                                  JSPrintValueWrite *write_func, void *write_opaque,
+                                  JSValueConst val, const JSPrintValueOptions *options)
 {
     JSPrintValueState ss, *s = &ss;
     if (options)
@@ -13546,32 +13579,52 @@ static void JS_PrintValueInternal(JSRuntime *rt, JSContext *ctx,
         s->options.max_item_count = UINT32_MAX;
     s->rt = rt;
     s->ctx = ctx;
-    s->fo = fo;
+    s->write_func = write_func;
+    s->write_opaque = write_opaque;
     s->level = 0;
     js_print_value(s, val);
 }
 
-void JS_PrintValueRT(JSRuntime *rt, FILE *fo, JSValueConst val, const JSPrintValueOptions *options)
+void JS_PrintValueRT(JSRuntime *rt, JSPrintValueWrite *write_func, void *write_opaque,
+                     JSValueConst val, const JSPrintValueOptions *options)
 {
-    JS_PrintValueInternal(rt, NULL, fo, val, options);
+    JS_PrintValueInternal(rt, NULL, write_func, write_opaque, val, options);
 }
 
-void JS_PrintValue(JSContext *ctx, FILE *fo, JSValueConst val, const JSPrintValueOptions *options)
+void JS_PrintValue(JSContext *ctx, JSPrintValueWrite *write_func, void *write_opaque,
+                   JSValueConst val, const JSPrintValueOptions *options)
 {
-    JS_PrintValueInternal(ctx->rt, ctx, fo, val, options);
+    JS_PrintValueInternal(ctx->rt, ctx, write_func, write_opaque, val, options);
+}
+
+static void js_dump_value_write(void *opaque, const char *buf, size_t len)
+{
+    FILE *fo = opaque;
+    fwrite(buf, 1, len, fo);
+}
+
+static __maybe_unused void print_atom(JSContext *ctx, JSAtom atom)
+{
+    JSPrintValueState ss, *s = &ss;
+    memset(s, 0, sizeof(*s));
+    s->rt = ctx->rt;
+    s->ctx = ctx;
+    s->write_func = js_dump_value_write;
+    s->write_opaque = stdout;
+    js_print_atom(s, atom);
 }
 
 static __maybe_unused void JS_DumpValue(JSContext *ctx, const char *str, JSValueConst val)
 {
     printf("%s=", str);
-    JS_PrintValue(ctx, stdout, val, NULL);
+    JS_PrintValue(ctx, js_dump_value_write, stdout, val, NULL);
     printf("\n");
 }
 
 static __maybe_unused void JS_DumpValueRT(JSRuntime *rt, const char *str, JSValueConst val)
 {
     printf("%s=", str);
-    JS_PrintValueRT(rt, stdout, val, NULL);
+    JS_PrintValueRT(rt, js_dump_value_write, stdout, val, NULL);
     printf("\n");
 }
 
@@ -13605,7 +13658,7 @@ static __maybe_unused void JS_DumpObject(JSRuntime *rt, JSObject *p)
     options.max_depth = 1;
     options.show_hidden = TRUE;
     options.raw_dump = TRUE;
-    JS_PrintValueRT(rt, stdout, JS_MKPTR(JS_TAG_OBJECT, p), &options);
+    JS_PrintValueRT(rt, js_dump_value_write, stdout, JS_MKPTR(JS_TAG_OBJECT, p), &options);
 
     printf("\n");
 }
@@ -30508,7 +30561,7 @@ static void dump_byte_code(JSContext *ctx, int pass,
         has_pool_idx:
             printf(" %u: ", idx);
             if (idx < cpool_count) {
-                JS_PrintValue(ctx, stdout, cpool[idx], NULL);
+                JS_PrintValue(ctx, js_dump_value_write, stdout, cpool[idx], NULL);
             }
             break;
         case OP_FMT_atom:
diff --git a/quickjs.h b/quickjs.h
index b851cd9..53425a2 100644
--- a/quickjs.h
+++ b/quickjs.h
@@ -1117,7 +1117,6 @@ int JS_SetModuleExportList(JSContext *ctx, JSModuleDef *m,
 
 typedef struct {
     JS_BOOL show_hidden : 8; /* only show enumerable properties */
-    JS_BOOL show_closure : 8; /* show closure variables */
     JS_BOOL raw_dump : 8; /* avoid doing autoinit and avoid any malloc() call (for internal use) */
     uint32_t max_depth; /* recurse up to this depth, 0 = no limit */
     uint32_t max_string_length; /* print no more than this length for
@@ -1126,9 +1125,13 @@ typedef struct {
                                  arrays or objects, 0 = no limit */
 } JSPrintValueOptions;
 
+typedef void JSPrintValueWrite(void *opaque, const char *buf, size_t len);
+
 void JS_PrintValueSetDefaultOptions(JSPrintValueOptions *options);
-void JS_PrintValueRT(JSRuntime *rt, FILE *fo, JSValueConst val, const JSPrintValueOptions *options);
-void JS_PrintValue(JSContext *ctx, FILE *fo, JSValueConst val, const JSPrintValueOptions *options);
+void JS_PrintValueRT(JSRuntime *rt, JSPrintValueWrite *write_func, void *write_opaque,
+                     JSValueConst val, const JSPrintValueOptions *options);
+void JS_PrintValue(JSContext *ctx, JSPrintValueWrite *write_func, void *write_opaque,
+                   JSValueConst val, const JSPrintValueOptions *options);
 
 #undef js_unlikely
 #undef js_force_inline
diff --git a/run-test262.c b/run-test262.c
index d1fa4f3..3da79a0 100644
--- a/run-test262.c
+++ b/run-test262.c
@@ -372,6 +372,12 @@ static void enumerate_tests(const char *path)
           namelist_cmp_indirect);
 }
 
+static void js_print_value_write(void *opaque, const char *buf, size_t len)
+{
+    FILE *fo = opaque;
+    fwrite(buf, 1, len, fo);
+}
+
 static JSValue js_print(JSContext *ctx, JSValueConst this_val,
                         int argc, JSValueConst *argv)
 {
@@ -397,7 +403,7 @@ static JSValue js_print(JSContext *ctx, JSValueConst this_val,
                 fwrite(str, 1, len, outfile);
                 JS_FreeCString(ctx, str);
             } else {
-                JS_PrintValue(ctx, outfile, v, NULL);
+                JS_PrintValue(ctx, js_print_value_write, outfile, v, NULL);
             }
         }
         fputc('\n', outfile);