Index: Modules/posixmodule.c
===================================================================
--- Modules/posixmodule.c	(révision 80063)
+++ Modules/posixmodule.c	(copie de travail)
@@ -2688,18 +2688,22 @@
 	wchar_t *command;
 	if (!PyArg_ParseTuple(args, "u:system", &command))
 		return NULL;
+
+	Py_BEGIN_ALLOW_THREADS
+	sts = _wsystem(command);
+	Py_END_ALLOW_THREADS
 #else
+	PyObject *command_obj;
 	char *command;
-	if (!PyArg_ParseTuple(args, "s:system", &command))
+	if (!PyArg_ParseTuple(args, "O&:system", PyUnicode_FSConverter, &command_obj))
 		return NULL;
-#endif
+
+	command = bytes2str(command_obj, 1);
 	Py_BEGIN_ALLOW_THREADS
-#ifdef MS_WINDOWS
-	sts = _wsystem(command);
-#else
 	sts = system(command);
+	Py_END_ALLOW_THREADS
+	release_bytes(command_obj);
 #endif
-	Py_END_ALLOW_THREADS
 	return PyLong_FromLong(sts);
 }
 #endif