On Sat, Feb 7, 2009 at 6:13 PM, Stefan Behnel <[email protected]> wrote: > 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 >
I think the same... Then I'll review this and push fixes. > >> 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. > Well, I was partially wrong in the above comments... > 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. It will not matter until you get a segfault or strange results... ;-) > 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 > Yes, you are right, but then better for users to not forget the casts... In short, If we can do it better, go for it and push testcases+fixes... -- Lisandro Dalcín --------------- Centro Internacional de Métodos Computacionales en Ingeniería (CIMEC) Instituto de Desarrollo Tecnológico para la Industria Química (INTEC) Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) PTLC - Güemes 3450, (3000) Santa Fe, Argentina Tel/Fax: +54-(0)342-451.1594 _______________________________________________ Cython-dev mailing list [email protected] http://codespeak.net/mailman/listinfo/cython-dev
