The Python/C API manual mentions conversion functions from⁽¹⁾ and to⁽²⁾ void pointers, which seem to be the only way to use arbitrary length python integers in C.
PyLong_FromVoidPtr() and format
PyLong_AsVoidPtr() and formats
However, I haven't found⁽³⁾ in the manual, any indication about the way to use those void pointers to do whatever in C with those arbitrary long integers.
(3) : I tried a search for «voidptr», «void *» and «0&» but haven't thoroughly read it all yet.
Where can I find information about their inner structure or primitives to compute on them ?