cpython/Include/internal/pycore_crossinterp_data_registry.h

#ifndef Py_CORE_CROSSINTERP_DATA_REGISTRY_H
#  error "this header must not be included directly"
#endif


// For now we use a global registry of shareable classes.  An
// alternative would be to add a tp_* slot for a class's
// xidatafunc. It would be simpler and more efficient.

struct _xid_regitem;

_PyXIData_regitem_t;

_PyXIData_registry_t;

PyAPI_FUNC(int) _PyXIData_RegisterClass(
    _PyXIData_lookup_context_t *,
    PyTypeObject *,
    xidatafunc);
PyAPI_FUNC(int) _PyXIData_UnregisterClass(
    _PyXIData_lookup_context_t *,
    PyTypeObject *);

struct _xid_lookup_state { … };