diff --git a/Include/pystate.h b/Include/pystate.h
index b29ce2a..a8fcc73 100644
--- a/Include/pystate.h
+++ b/Include/pystate.h
@@ -139,6 +139,7 @@
 PyAPI_FUNC(void) _PyThreadState_Init(PyThreadState *);
 PyAPI_FUNC(void) PyThreadState_Clear(PyThreadState *);
 PyAPI_FUNC(void) PyThreadState_Delete(PyThreadState *);
+PyAPI_FUNC(void) _PyThreadState_DeleteExcept(PyThreadState *tstate);
 #ifdef WITH_THREAD
 PyAPI_FUNC(void) PyThreadState_DeleteCurrent(void);
 PyAPI_FUNC(void) _PyGILState_Reinit(void);