diff --git a/Python/ast.c b/Python/ast.c
index b08cf9b..1c79359 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -3162,18 +3162,18 @@
 #ifndef WITHOUT_COMPLEX
     if (imflag) {
         compl.real = 0.;
-        PyFPE_START_PROTECT("atof", return 0)
-            compl.imag = PyOS_ascii_atof(s);
-        PyFPE_END_PROTECT(c)
-            return PyComplex_FromCComplex(compl);
+        compl.imag = PyOS_string_to_double(s, (char **)&end, NULL);
+        if (compl.imag == -1.0 && PyErr_Occurred())
+            return NULL;
+        return PyComplex_FromCComplex(compl);
     }
     else
 #endif
     {
-        PyFPE_START_PROTECT("atof", return 0)
-            dx = PyOS_ascii_atof(s);
-        PyFPE_END_PROTECT(dx)
-            return PyFloat_FromDouble(dx);
+        dx = PyOS_string_to_double(s, NULL, NULL);
+        if (dx == -1.0 && PyErr_Occurred())
+            return NULL;
+        return PyFloat_FromDouble(dx);
     }
 }