documentation on internals not up to date

[Marc Glisse]

On Fri, 27 Apr 2018, Niels Möller wrote:

>>> _mp_alloc == 0 and _mp_size != 0 is a read-only value, _mp_d is neither
>>> written, reallocated or freed by mpz functions. It must not be passed as
>>> destination argument to any mpz function. Should also link to docs for
>>> mpz_roinit_n and MPZ_ROINIT_N.
>>
>> Currently, if an mpz_t is initialised with _roinit, it can be passed to
>> _clear or _clears with no errors. Should we document this? I think we
>> should.
>>
>> Moreover, the various mpz_set_ functions should work smoothly too.
>
> I'd prefer that we not document any way to pass _roinit values to any
> mpz functions taking a non-const mpz_t, even if it happens to work in
> the current implementation. Maybe as a later extension, *if* we find
> some use cases where it provides a significant advantage.

There would be a significant advantage to mpq if we could have a
non-allocated 1 for the denominator. But indeed, with the current code 
where only some mpz functions would work, it seems safer to document that 
none work.

-- 
Marc Glisse