An optional argument if not passed isn't modified by the PyArg_ParseTuple function. Signed-off-by: Pavel Hrdina <phrdina(a)redhat.com&gt; --- Sigh :/, pushed as trivial libvirt-override.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libvirt-override.c b/libvirt-override.c index a461eda..a53b46f 100644 --- a/libvirt-override.c +++ b/libvirt-override.c @@ -8171,7 +8171,7 @@ libvirt_virDomainBlockCopy(PyObject *self ATTRIBUTE_UNUSED, PyObject *args) char *destxml = NULL; virTypedParameterPtr params = NULL; int nparams = 0; - unsigned int flags; + unsigned int flags = 0; int c_retval; if (!PyArg_ParseTuple(args, (char *) "Ozz|OI:virDomainBlockCopy",