Index: Lib/test/test_locale.py
===================================================================
--- Lib/test/test_locale.py	(revision 78171)
+++ Lib/test/test_locale.py	(working copy)
@@ -364,6 +364,23 @@
         # crasher from bug #7419
         self.assertRaises(locale.Error, locale.setlocale, 12345)
 
+    def test_set_ctype_before_mbstowcs(self):
+        # Issue 7442
+        lc_ctype = locale.setlocale(locale.LC_CTYPE)
+        lc_numeric = locale.setlocale(locale.LC_NUMERIC)
+        lc_monetary = locale.setlocale(locale.LC_MONETARY)
+        locale.setlocale(locale.LC_CTYPE, 'C')
+        try:
+            locale.setlocale(locale.LC_NUMERIC, 'fi_FI')
+            locale.setlocale(locale.LC_MONETARY, 'fi_FI')
+        except locale.Error:
+            pass
+        try:
+            locale.localeconv()
+        finally:
+            locale.setlocale(locale.LC_CTYPE, lc_ctype)
+            locale.setlocale(locale.LC_NUMERIC, lc_numeric)
+            locale.setlocale(locale.LC_MONETARY, lc_monetary)
 
 def test_main():
     tests = [
Index: Modules/_localemodule.c
===================================================================
--- Modules/_localemodule.c	(revision 78171)
+++ Modules/_localemodule.c	(working copy)
@@ -164,6 +164,16 @@
     return result_object;
 }
 
+static char *
+localedup(int category)
+{
+	char *locale;
+
+	if ((locale = setlocale(category, NULL)) == NULL)
+		return NULL;
+	return strdup(locale);
+}
+
 PyDoc_STRVAR(localeconv__doc__,
 "() -> dict. Returns numeric and monetary locale-specific parameters.");
 
@@ -172,7 +182,11 @@
 {
     PyObject* result;
     struct lconv *l;
-    PyObject *x;
+    PyObject *x = NULL;
+    char *lc_numeric = NULL;
+    char *lc_monetary = NULL;
+    char *lc_ctype = NULL;
+    int   set_ctype = 0;
 
     result = PyDict_New();
     if (!result)
@@ -196,7 +210,17 @@
     PyDict_SetItemString(result, #i, x);\
     Py_XDECREF(x)
 
+    lc_ctype = localedup(LC_CTYPE);
+    lc_numeric = localedup(LC_NUMERIC);
+    lc_monetary = localedup(LC_MONETARY);
+    if (!lc_ctype || !lc_numeric || !lc_monetary)
+        goto failed;
+
     /* Numeric information */
+    if (strcmp(lc_numeric, lc_ctype)) {
+        set_ctype = 1;
+        setlocale(LC_CTYPE, lc_numeric);
+    }
     RESULT_STRING(decimal_point);
     RESULT_STRING(thousands_sep);
     x = copy_grouping(l->grouping);
@@ -206,6 +230,10 @@
     Py_XDECREF(x);
 
     /* Monetary information */
+    if (strcmp(lc_monetary, set_ctype?lc_numeric:lc_ctype)) {
+        set_ctype = 1;
+        setlocale(LC_CTYPE, lc_monetary);
+    }
     RESULT_STRING(int_curr_symbol);
     RESULT_STRING(currency_symbol);
     RESULT_STRING(mon_decimal_point);
@@ -225,12 +253,22 @@
     RESULT_INT(n_sep_by_space);
     RESULT_INT(p_sign_posn);
     RESULT_INT(n_sign_posn);
+
+  out:
+    if (lc_ctype) {
+        if (set_ctype) 
+            setlocale(LC_CTYPE, lc_ctype);
+        free(lc_ctype);
+    }
+    if (lc_numeric) free(lc_numeric);
+    if (lc_monetary) free(lc_monetary);
     return result;
 
   failed:
     Py_XDECREF(result);
     Py_XDECREF(x);
-    return NULL;
+    result = NULL;
+    goto out;
 }
 
 #if defined(HAVE_WCSCOLL)
@@ -549,7 +587,7 @@
 
 PyDoc_STRVAR(textdomain__doc__,
 "textdomain(domain) -> string\n"
-"Set the C library's textdmain to domain, returning the new domain.");
+"Set the C library's textdomain to domain, returning the new domain.");
 
 static PyObject*
 PyIntl_textdomain(PyObject* self, PyObject* args)