[Python-Dev] C99

Christian Heimes christian at python.org
Sat Jun 4 13:27:39 EDT 2016

On 2016-06-03 23:11, Benjamin Peterson wrote:
> PEP 7 requires CPython to use C code conforming to the venerable C89
> standard. Traditionally, we've been stuck with C89 due to poor C support
> in MSVC. However, MSVC 2013 and 2015 implement the key features of C99.
> C99 does not offer anything earth-shattering; here are the features I
> think we'd find most interesting:
> - Variable declarations can be on any line: removes possibly the most
> annoying limitation of C89.
> - Inline functions: We can make Py_DECREF and Py_INCREF inline functions
> rather than unpleasant macros.
> - C++-style line comments: Not an killer feature but commonly used.
> - Booleans
> In summary, some niceties that would make CPython hacking a little more
> fun.
> So, what say you to updating PEP 7 to allow C99 features for Python 3.6
> (in so much as GCC and MSVC support them)?


- We never officially deprecated C89 platforms withou 64 bit integers in
PEP 7. Victor's changes to pytime.h implies support for uint64_t and
int64_t. C99 has mandatory long long int support.

- If we also drop Solaris Studio C compiler support, we can replace
header guards (e.g. #ifndef Py_PYTHON_H) with #pragma once


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