Hi,
Lisandro Dalcin wrote:
> Could we assume that PY_LONG_LONG is the widest integral?? Should we
> assume that 'Py_ssize_t' and 'size_t' are between 'long' and
> 'PY_LONG_LONG'?
For starters, Py_ssize_t is defined as a signed size_t according to PEP
353. However, it does not mention a relation to PY_LONG_LONG.
I would at least expect Py_ssize_t to be <= PY_LONG_LONG (the latter being
the largest available type), and my (limited) knowledge about the "long"
type makes me assume that it should be <= Py_ssize_t. So, yes, I would expect
long <= Py_ssize_t <= PY_LONG_LONG
and
unsigned long <= size_t <= unsigned PY_LONG_LONG
> However, I'm not sure how to we will handle code like the one below
> with the current implementation,
>
> cdef f():
> cdef Py_ssize_t a = 5
> cdef size_t b = 7
> return a + b
>
> I believe the value of 'a+b' should be promoted to 'signed long long',
> but it cannot see the way to implent such behavior in the current
> Cython codebase.
Wouldn't Py_ssize_t be a suitable target type? Admittedly, it's << size_t
for non-negative types, but the missing bit shouldn't matter in almost all
cases. And if users really need to make use of it, I'm fine with requiring
them to write
return <PY_LONG_LONG>a + <PY_LONG_LONG>b
Stefan
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