diff --git a/include/mruby/value.h b/include/mruby/value.h
index 846452ce6..b791b7676 100644
--- a/include/mruby/value.h
+++ b/include/mruby/value.h
@@ -100,7 +100,9 @@ struct mrb_state;
 # define MRB_ENDIAN_LOHI(a,b) b a
 #endif
 
-MRB_API mrb_int mrb_int_read(const char *p, const char *e, char **endp);
+MRB_API mrb_bool mrb_read_int(const char *p, const char *e, char **endp, mrb_int *np);
+/* obsolete; do not use mrb_int_read() */
+MRB_API mrb_int mrb_int_read(const char*, const char*, char**);
 #ifndef MRB_NO_FLOAT
 MRB_API double mrb_float_read(const char*, char**);
 #ifdef MRB_USE_FLOAT32
diff --git a/mrbgems/mruby-compiler/core/parse.y b/mrbgems/mruby-compiler/core/parse.y
index d4258750f..9f4765771 100644
--- a/mrbgems/mruby-compiler/core/parse.y
+++ b/mrbgems/mruby-compiler/core/parse.y
@@ -6328,8 +6328,8 @@ parser_yylex(parser_state *p)
       if (last_state == EXPR_FNAME) goto gvar;
       tokfix(p);
       {
-        mrb_int n = mrb_int_read(tok(p), NULL, NULL);
-        if (n > INT32_MAX) {
+        mrb_int n;
+        if (!mrb_read_int(tok(p), NULL, NULL, &n)) {
           yywarning(p, "capture group index too big; always nil");
           return keyword_nil;
         }
diff --git a/mrbgems/mruby-compiler/core/y.tab.c b/mrbgems/mruby-compiler/core/y.tab.c
index c818f299c..7d0d9b82c 100644
--- a/mrbgems/mruby-compiler/core/y.tab.c
+++ b/mrbgems/mruby-compiler/core/y.tab.c
@@ -12524,8 +12524,8 @@ parser_yylex(parser_state *p)
       if (last_state == EXPR_FNAME) goto gvar;
       tokfix(p);
       {
-        mrb_int n = mrb_int_read(tok(p), NULL, NULL);
-        if (n > INT32_MAX) {
+        mrb_int n;
+        if (!mrb_read_int(tok(p), NULL, NULL, &n)) {
           yywarning(p, "capture group index too big; always nil");
           return keyword_nil;
         }
diff --git a/mrbgems/mruby-pack/src/pack.c b/mrbgems/mruby-pack/src/pack.c
index de667362f..48a820208 100644
--- a/mrbgems/mruby-pack/src/pack.c
+++ b/mrbgems/mruby-pack/src/pack.c
@@ -1306,8 +1306,8 @@ alias:
     ch = tptr[tmpl->idx];
     if (ISDIGIT(ch)) {
       char *e;
-      mrb_int n = mrb_int_read(tptr+tmpl->idx, tptr+tlen, &e);
-      if (e == NULL || n > INT_MAX) {
+      mrb_int n;
+      if (!mrb_read_int(tptr+tmpl->idx, tptr+tlen, &e, &n)) {
         mrb_raise(mrb, E_RUNTIME_ERROR, "too big template length");
       }
       count = (int)n;
diff --git a/mrbgems/mruby-sprintf/src/sprintf.c b/mrbgems/mruby-sprintf/src/sprintf.c
index 2ceaffd5f..7104a185a 100644
--- a/mrbgems/mruby-sprintf/src/sprintf.c
+++ b/mrbgems/mruby-sprintf/src/sprintf.c
@@ -254,12 +254,14 @@ check_name_arg(mrb_state *mrb, int posarg, const char *name, size_t len)
   num = (int)mrb_as_int(mrb, tmp_v); \
 } while (0)
 
-static const char *
+static const char*
 get_num(mrb_state *mrb, const char *p, const char *end, int *valp)
 {
   char *e;
-  mrb_int n = mrb_int_read(p, end, &e);
-  if (e == NULL || n > INT_MAX) return NULL;
+  mrb_int n;
+  if (!mrb_read_int(p, end, &e, &n)) {
+    return NULL;
+  }
   *valp = (int)n;
   return e;
 }
diff --git a/src/readint.c b/src/readint.c
index 5fae222c2..ad7c048e7 100644
--- a/src/readint.c
+++ b/src/readint.c
@@ -1,16 +1,15 @@
 #include <mruby.h>
 #include <mruby/numeric.h>
-#include <errno.h>
 
-/* mrb_int_read(): read mrb_int from a string (base 10 only) */
+/* mrb_read_int(): read mrb_int from a string (base 10 only) */
 /* const char *p - string to read                            */
 /* const char *e - end of string                             */
 /* char **endp   - end of parsed integer                     */
-
-/* if integer overflows, errno will be set to ERANGE         */
-/* also endp will be set to NULL on overflow                 */
-MRB_API mrb_int
-mrb_int_read(const char *p, const char *e, char **endp)
+/* mrb_int *np   - variable to save the result               */
+/* returns TRUE if read succeeded                            */
+/* if integer overflows, returns FALSE                       */
+MRB_API mrb_bool
+mrb_read_int(const char *p, const char *e, char **endp, mrb_int *np)
 {
   mrb_int n = 0;
   int ch;
@@ -19,12 +18,11 @@ mrb_int_read(const char *p, const char *e, char **endp)
     ch = *p - '0';
     if (mrb_int_mul_overflow(n, 10, &n) ||
         mrb_int_add_overflow(n, ch, &n)) {
-      if (endp) *endp = NULL;
-      errno = ERANGE;
-      return MRB_INT_MAX;
+      return FALSE;
     }
     p++;
   }
   if (endp) *endp = (char*)p;
-  return n;
+  *np = n;
+  return TRUE;
 }