PyThreadState_SetAsyncExc and native extensions

[gabriel.becedillas]

Does anyone know if PyThreadState_SetAsyncExc stops a thread while its
inside a native extension ?
I'm trying to stop a testing script that boils down to this:

while True:
print "aaa"
native_extension_call()
print "bbb"

Using PyThreadState_SetAsyncExc the module doesn't stop but if I add
more print statements to increase the chance that
PyThreadState_SetAsyncExc is called when the module is executing Python
code, the module stops.