diff --git a/dlls/api-ms-win-crt-convert-l1-1-0/api-ms-win-crt-convert-l1-1-0.spec b/dlls/api-ms-win-crt-convert-l1-1-0/api-ms-win-crt-convert-l1-1-0.spec
index 8cbb1849ffe..a67828e6d22 100644
--- a/dlls/api-ms-win-crt-convert-l1-1-0/api-ms-win-crt-convert-l1-1-0.spec
+++ b/dlls/api-ms-win-crt-convert-l1-1-0/api-ms-win-crt-convert-l1-1-0.spec
@@ -9,7 +9,7 @@
 @ cdecl _atoi_l(str ptr) ucrtbase._atoi_l
 @ cdecl _atol_l(str ptr) ucrtbase._atol_l
 @ cdecl _atoldbl(ptr str) ucrtbase._atoldbl
-@ stub _atoldbl_l
+@ cdecl _atoldbl_l(ptr str ptr) ucrtbase._atoldbl_l
 @ cdecl -ret64 _atoll_l(str ptr) ucrtbase._atoll_l
 @ cdecl _ecvt(double long ptr ptr) ucrtbase._ecvt
 @ cdecl _ecvt_s(str long double long ptr ptr) ucrtbase._ecvt_s
diff --git a/dlls/api-ms-win-crt-private-l1-1-0/api-ms-win-crt-private-l1-1-0.spec b/dlls/api-ms-win-crt-private-l1-1-0/api-ms-win-crt-private-l1-1-0.spec
index af84ff943b5..f74cea4e14c 100644
--- a/dlls/api-ms-win-crt-private-l1-1-0/api-ms-win-crt-private-l1-1-0.spec
+++ b/dlls/api-ms-win-crt-private-l1-1-0/api-ms-win-crt-private-l1-1-0.spec
@@ -187,7 +187,7 @@
 @ cdecl _o__atoi_l(str ptr) ucrtbase._o__atoi_l
 @ cdecl _o__atol_l(str ptr) ucrtbase._o__atol_l
 @ cdecl _o__atoldbl(ptr str) ucrtbase._o__atoldbl
-@ stub _o__atoldbl_l
+@ cdecl _o__atoldbl_l(ptr str ptr) ucrtbase._o__atoldbl_l
 @ cdecl -ret64 _o__atoll_l(str ptr) ucrtbase._o__atoll_l
 @ cdecl _o__beep(long long) ucrtbase._o__beep
 @ cdecl _o__beginthread(ptr long ptr) ucrtbase._o__beginthread
diff --git a/dlls/msvcr100/msvcr100.spec b/dlls/msvcr100/msvcr100.spec
index 12699a71fa3..a396ee38a76 100644
--- a/dlls/msvcr100/msvcr100.spec
+++ b/dlls/msvcr100/msvcr100.spec
@@ -562,7 +562,7 @@
 @ cdecl __RTDynamicCast(ptr long ptr ptr long) MSVCRT___RTDynamicCast
 @ cdecl __RTtypeid(ptr) MSVCRT___RTtypeid
 @ cdecl __STRINGTOLD(ptr ptr str long)
-@ stub __STRINGTOLD_L
+@ cdecl __STRINGTOLD_L(ptr ptr str long ptr)
 @ stub __TypeMatch
 @ cdecl ___lc_codepage_func()
 @ cdecl ___lc_collate_cp_func()
@@ -701,7 +701,7 @@
 @ cdecl _atoi_l(str ptr) MSVCRT__atoi_l
 @ cdecl _atol_l(str ptr) MSVCRT__atol_l
 @ cdecl _atoldbl(ptr str) MSVCRT__atoldbl
-@ stub _atoldbl_l
+@ cdecl _atoldbl_l(ptr str ptr) MSVCRT__atoldbl_l
 @ cdecl _beep(long long) MSVCRT__beep
 @ cdecl _beginthread(ptr long ptr)
 @ cdecl _beginthreadex(ptr long ptr ptr long ptr)
diff --git a/dlls/msvcr110/msvcr110.spec b/dlls/msvcr110/msvcr110.spec
index 785baaef610..b91a5df3ab4 100644
--- a/dlls/msvcr110/msvcr110.spec
+++ b/dlls/msvcr110/msvcr110.spec
@@ -889,7 +889,7 @@
 @ cdecl __RTDynamicCast(ptr long ptr ptr long) MSVCRT___RTDynamicCast
 @ cdecl __RTtypeid(ptr) MSVCRT___RTtypeid
 @ cdecl __STRINGTOLD(ptr ptr str long)
-@ stub __STRINGTOLD_L
+@ cdecl __STRINGTOLD_L(ptr ptr str long ptr)
 @ stub __TypeMatch
 @ cdecl ___lc_codepage_func()
 @ cdecl ___lc_collate_cp_func()
@@ -1049,7 +1049,7 @@
 @ cdecl _atoi_l(str ptr) MSVCRT__atoi_l
 @ cdecl _atol_l(str ptr) MSVCRT__atol_l
 @ cdecl _atoldbl(ptr str) MSVCRT__atoldbl
-@ stub _atoldbl_l
+@ cdecl _atoldbl_l(ptr str ptr) MSVCRT__atoldbl_l
 @ cdecl _beep(long long) MSVCRT__beep
 @ cdecl _beginthread(ptr long ptr)
 @ cdecl _beginthreadex(ptr long ptr ptr long ptr)
diff --git a/dlls/msvcr120/msvcr120.spec b/dlls/msvcr120/msvcr120.spec
index 83daf454b62..dd7d48a8629 100644
--- a/dlls/msvcr120/msvcr120.spec
+++ b/dlls/msvcr120/msvcr120.spec
@@ -874,7 +874,7 @@
 @ cdecl __RTDynamicCast(ptr long ptr ptr long) MSVCRT___RTDynamicCast
 @ cdecl __RTtypeid(ptr) MSVCRT___RTtypeid
 @ cdecl __STRINGTOLD(ptr ptr str long)
-@ stub __STRINGTOLD_L
+@ cdecl __STRINGTOLD_L(ptr ptr str long ptr)
 @ stub __TypeMatch
 @ cdecl ___lc_codepage_func()
 @ cdecl ___lc_collate_cp_func()
@@ -1039,7 +1039,7 @@
 @ cdecl _atoi_l(str ptr) MSVCRT__atoi_l
 @ cdecl _atol_l(str ptr) MSVCRT__atol_l
 @ cdecl _atoldbl(ptr str) MSVCRT__atoldbl
-@ stub _atoldbl_l
+@ cdecl _atoldbl_l(ptr str ptr) MSVCRT__atoldbl_l
 @ cdecl -ret64 _atoll_l(str ptr) MSVCRT__atoll_l
 @ cdecl _beep(long long) MSVCRT__beep
 @ cdecl _beginthread(ptr long ptr)
diff --git a/dlls/msvcr120_app/msvcr120_app.spec b/dlls/msvcr120_app/msvcr120_app.spec
index 100599e2b2d..b8ffbbc7581 100644
--- a/dlls/msvcr120_app/msvcr120_app.spec
+++ b/dlls/msvcr120_app/msvcr120_app.spec
@@ -868,7 +868,7 @@
 @ cdecl __RTDynamicCast(ptr long ptr ptr long) msvcr120.__RTDynamicCast
 @ cdecl __RTtypeid(ptr) msvcr120.__RTtypeid
 @ cdecl __STRINGTOLD(ptr ptr str long) msvcr120.__STRINGTOLD
-@ stub __STRINGTOLD_L
+@ cdecl __STRINGTOLD_L(ptr ptr str long ptr) msvcr120.__STRINGTOLD_L
 @ stub __TypeMatch
 @ cdecl ___lc_codepage_func() msvcr120.___lc_codepage_func
 @ cdecl ___lc_collate_cp_func() msvcr120.___lc_collate_cp_func
@@ -1010,7 +1010,7 @@
 @ cdecl _atoi_l(str ptr) msvcr120._atoi_l
 @ cdecl _atol_l(str ptr) msvcr120._atol_l
 @ cdecl _atoldbl(ptr str) msvcr120._atoldbl
-@ stub _atoldbl_l
+@ cdecl _atoldbl_l(ptr str ptr) msvcr120._atoldbl_l
 @ cdecl -ret64 _atoll_l(str ptr) msvcr120._atoll_l
 @ cdecl _byteswap_uint64(int64) msvcr120._byteswap_uint64
 @ cdecl _byteswap_ulong(long) msvcr120._byteswap_ulong
diff --git a/dlls/msvcr80/msvcr80.spec b/dlls/msvcr80/msvcr80.spec
index 4a5e0875c26..4050750123a 100644
--- a/dlls/msvcr80/msvcr80.spec
+++ b/dlls/msvcr80/msvcr80.spec
@@ -196,7 +196,7 @@
 @ cdecl __RTDynamicCast(ptr long ptr ptr long) MSVCRT___RTDynamicCast
 @ cdecl __RTtypeid(ptr) MSVCRT___RTtypeid
 @ cdecl __STRINGTOLD(ptr ptr str long)
-@ stub __STRINGTOLD_L
+@ cdecl __STRINGTOLD_L(ptr ptr str long ptr)
 @ stub __TypeMatch
 @ cdecl ___lc_codepage_func()
 @ cdecl ___lc_collate_cp_func()
@@ -365,7 +365,7 @@
 @ cdecl _atoi_l(str ptr) MSVCRT__atoi_l
 @ cdecl _atol_l(str ptr) MSVCRT__atol_l
 @ cdecl _atoldbl(ptr str) MSVCRT__atoldbl
-@ stub _atoldbl_l
+@ cdecl _atoldbl_l(ptr str ptr) MSVCRT__atoldbl_l
 @ cdecl _beep(long long) MSVCRT__beep
 @ cdecl _beginthread(ptr long ptr)
 @ cdecl _beginthreadex(ptr long ptr ptr long ptr)
diff --git a/dlls/msvcr90/msvcr90.spec b/dlls/msvcr90/msvcr90.spec
index 5401cd2a9c4..5208d3e5f35 100644
--- a/dlls/msvcr90/msvcr90.spec
+++ b/dlls/msvcr90/msvcr90.spec
@@ -187,7 +187,7 @@
 @ cdecl __RTDynamicCast(ptr long ptr ptr long) MSVCRT___RTDynamicCast
 @ cdecl __RTtypeid(ptr) MSVCRT___RTtypeid
 @ cdecl __STRINGTOLD(ptr ptr str long)
-@ stub __STRINGTOLD_L
+@ cdecl __STRINGTOLD_L(ptr ptr str long ptr)
 @ stub __TypeMatch
 @ cdecl ___lc_codepage_func()
 @ cdecl ___lc_collate_cp_func()
@@ -349,7 +349,7 @@
 @ cdecl _atoi_l(str ptr) MSVCRT__atoi_l
 @ cdecl _atol_l(str ptr) MSVCRT__atol_l
 @ cdecl _atoldbl(ptr str) MSVCRT__atoldbl
-@ stub _atoldbl_l
+@ cdecl _atoldbl_l(ptr str ptr) MSVCRT__atoldbl_l
 @ cdecl _beep(long long) MSVCRT__beep
 @ cdecl _beginthread(ptr long ptr)
 @ cdecl _beginthreadex(ptr long ptr ptr long ptr)
diff --git a/dlls/msvcrt/msvcrt.spec b/dlls/msvcrt/msvcrt.spec
index 36284cf14aa..2dc9c87e57a 100644
--- a/dlls/msvcrt/msvcrt.spec
+++ b/dlls/msvcrt/msvcrt.spec
@@ -336,7 +336,7 @@
 @ cdecl _atoi_l(str ptr) MSVCRT__atoi_l
 @ cdecl _atol_l(str ptr) MSVCRT__atol_l
 @ cdecl _atoldbl(ptr str) MSVCRT__atoldbl
-# stub _atoldbl_l(ptr str ptr)
+@ cdecl _atoldbl_l(ptr str ptr) MSVCRT__atoldbl_l
 @ cdecl _beep(long long) MSVCRT__beep
 @ cdecl _beginthread (ptr long ptr)
 @ cdecl _beginthreadex (ptr long ptr ptr long ptr)
diff --git a/dlls/msvcrt/string.c b/dlls/msvcrt/string.c
index 30b2525692b..806dace0409 100644
--- a/dlls/msvcrt/string.c
+++ b/dlls/msvcrt/string.c
@@ -1233,30 +1233,14 @@ MSVCRT_size_t CDECL MSVCRT_strxfrm( char *dest, const char *src, MSVCRT_size_t l
 }
 
 /********************************************************************
- *		_atoldbl (MSVCRT.@)
+ *		__STRINGTOLD_L (MSVCR80.@)
  */
-int CDECL MSVCRT__atoldbl(MSVCRT__LDOUBLE *value, const char *str)
-{
-  /* FIXME needs error checking for huge/small values */
-#ifdef HAVE_STRTOLD
-  long double ld;
-  TRACE("str %s value %p\n",str,value);
-  ld = strtold(str,0);
-  memcpy(value, &ld, 10);
-#else
-  FIXME("stub, str %s value %p\n",str,value);
-#endif
-  return 0;
-}
-
-/********************************************************************
- *		__STRINGTOLD (MSVCRT.@)
- */
-int CDECL __STRINGTOLD( MSVCRT__LDOUBLE *value, char **endptr, const char *str, int flags )
+int CDECL __STRINGTOLD_L( MSVCRT__LDOUBLE *value, char **endptr,
+        const char *str, int flags, MSVCRT__locale_t locale )
 {
 #ifdef HAVE_STRTOLD
     long double ld;
-    FIXME("%p %p %s %x partial stub\n", value, endptr, str, flags );
+    FIXME("%p %p %s %x %p partial stub\n", value, endptr, str, flags, locale );
     ld = strtold(str,0);
     memcpy(value, &ld, 10);
 #else
@@ -1265,6 +1249,36 @@ int CDECL __STRINGTOLD( MSVCRT__LDOUBLE *value, char **endptr, const char *str,
     return 0;
 }
 
+/********************************************************************
+ *              __STRINGTOLD (MSVCRT.@)
+ */
+int CDECL __STRINGTOLD( MSVCRT__LDOUBLE *value, char **endptr, const char *str, int flags )
+{
+    return __STRINGTOLD_L( value, endptr, str, flags, NULL );
+}
+
+/********************************************************************
+ *              _atoldbl_l (MSVCRT.@)
+ */
+int CDECL MSVCRT__atoldbl_l( MSVCRT__LDOUBLE *value, const char *str, MSVCRT__locale_t locale )
+{
+    char *endptr;
+    switch(__STRINGTOLD_L( value, &endptr, str, 0, locale ))
+    {
+    case 1: return MSVCRT__UNDERFLOW;
+    case 2: return MSVCRT__OVERFLOW;
+    default: return 0;
+    }
+}
+
+/********************************************************************
+ *		_atoldbl (MSVCRT.@)
+ */
+int CDECL MSVCRT__atoldbl(MSVCRT__LDOUBLE *value, const char *str)
+{
+    return MSVCRT__atoldbl_l( value, str, NULL );
+}
+
 /*********************************************************************
  *              strlen (MSVCRT.@)
  */
diff --git a/dlls/ucrtbase/ucrtbase.spec b/dlls/ucrtbase/ucrtbase.spec
index 6dc73d47fd5..689b3d7c951 100644
--- a/dlls/ucrtbase/ucrtbase.spec
+++ b/dlls/ucrtbase/ucrtbase.spec
@@ -200,7 +200,7 @@
 @ cdecl _atoi_l(str ptr) MSVCRT__atoi_l
 @ cdecl _atol_l(str ptr) MSVCRT__atol_l
 @ cdecl _atoldbl(ptr str) MSVCRT__atoldbl
-@ stub _atoldbl_l
+@ cdecl _atoldbl_l(ptr str ptr) MSVCRT__atoldbl_l
 @ cdecl -ret64 _atoll_l(str ptr) MSVCRT__atoll_l
 @ cdecl _beep(long long) MSVCRT__beep
 @ cdecl _beginthread(ptr long ptr)
@@ -851,7 +851,7 @@
 @ cdecl _o__atoi_l(str ptr) MSVCRT__atoi_l
 @ cdecl _o__atol_l(str ptr) MSVCRT__atol_l
 @ cdecl _o__atoldbl(ptr str) MSVCRT__atoldbl
-@ stub _o__atoldbl_l
+@ cdecl _o__atoldbl_l(ptr str ptr) MSVCRT__atoldbl_l
 @ cdecl -ret64 _o__atoll_l(str ptr) MSVCRT__atoll_l
 @ cdecl _o__beep(long long) MSVCRT__beep
 @ cdecl _o__beginthread(ptr long ptr) _beginthread