[Python-Dev] Py_SIZE vs PyXXX_GET_SIZE

[Benjamin Peterson]

On Mon, Mar 20, 2017, at 13:18, Antoine Pitrou wrote:
> On Mon, 20 Mar 2017 13:26:34 +0200
> Serhiy Storchaka <storchaka at gmail.com> wrote:
> > What is the preferable way of getting the size of tuple, list, bytes, 
> > bytearray: Py_SIZE or PyTuple_GET_SIZE, PyList_GET_SIZE, 
> > PyBytes_GET_SIZE, PyByteArray_GET_SIZE? Are macros for concrete types 
> > more preferable or they are outdated?
> 
> +1 for using concrete macros.  Py_SIZE is a low-level internal thing
> (e.g. it will return a negative size on negative ints).

+1 Py_SIZE is an implementation detail of varsize types. Using the
concrete macros also the implementation to change without altering API
consumers.