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[Python-Dev] Missing functions [Was: Re: Experiment an opt-in new C API for Python? (leave current API unchanged)]


On 11/21/18 4:11 PM, Mat?j Cepl wrote:
> On 2018-11-21, 14:54 GMT, Benjamin Peterson wrote:
>> In Python 3, there is no underlying FILE* because the io
>> module is implemented using fds directly rather than C stdio.
> 
> OK, so the proper solution is to kill all functions which expect
> FILE

Indeed.
This has another side to it: there are file-like objects that aren't 
backed by FILE*. In most case, being a "real" file is an unnecessary 
distinction, like that between the old `int` vs. `long`. "Fits in the 
machine register" is a detail from a level below Python, and so is "the 
kernel treats this as a file".

Of course, this is not how C libraries work -- so, sadly, it makes 
wrappers harder to write. And a perfect solution might require adding 
more generic I/O to the C library.


> and if you are anal retentive about stability of API, then
> you have to fake it by creating FILE structure around the
> underlying fd handler as I did in M2Crypto, right?

Yes, AFAIK that is the least bad solution.
I did something very similar here: 
https://github.com/encukou/py3c/blob/master/include/py3c/fileshim.h