From: Ryan Johnson <ryan.johnson@cs.utoronto.ca>
To: cygwin@cygwin.com
Subject: Re: siginfo_t missing member si_band
Date: Tue, 15 Oct 2013 21:14:00 -0000 [thread overview]
Message-ID: <525DB015.1010707@cs.utoronto.ca> (raw)
In-Reply-To: <20131015194242.GA2368@ednor.casa.cgf.cx>
On 15/10/2013 3:42 PM, Christopher Faylor wrote:
> On Tue, Oct 15, 2013 at 10:48:19AM -0400, Ryan Johnson wrote:
>> Hi all,
>>
>> While trying to build python3 for cygwin, I kept encountering the
>> following error message:
>>
>> ./Modules/signalmodule.c: In function ?fill_siginfo?:
>> ./Modules/signalmodule.c:745:60: error: ?siginfo_t? has no member named
>> ?si_band?
>> PyStructSequence_SET_ITEM(result, 6, PyLong_FromLong(si->si_band));
>> ^
>> Include/tupleobject.h:62:75: note: in definition of macro
>> ?PyTuple_SET_ITEM?
>> #define PyTuple_SET_ITEM(op, i, v) (((PyTupleObject *)(op))->ob_item[i]
>> = v)
>> ^
>> ./Modules/signalmodule.c:745:5: note: in expansion of macro
>> ?PyStructSequence_SET_ITEM?
>> PyStructSequence_SET_ITEM(result, 6, PyLong_FromLong(si->si_band));
>>
>> As far as I can tell, siginfo_t::si_band is mandated by POSIX.1-2001,
>> and required for proper handling of SIGPOLL. The latter seems to
>> correspond to async I/O with poll(2). I'm pretty sure cygwin doesn't
>> support async I/O, but shouldn't the struct member at least exist, to
>> avoid breaking code that assumes its existence? The alternative is to
>> patch python3 locally so its os.sigwaitinfo function no longer touches
>> si_band, or to file a bug upstream so that the module's configury tests
>> for its existence before using it.
>>
>> Thoughts?
> Sure. I question the utility of lying in a structure about the
> availability of an unimplemented feature. If something is specifically
> expecting the structure member to exist it seems like it would be
> expecting it to do something.
So that would be a vote for filing a bug upstream with python's FFI
interface to signal handling? Fair enough.
Ryan
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next prev parent reply other threads:[~2013-10-15 21:14 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-15 14:48 Ryan Johnson
2013-10-15 19:42 ` Christopher Faylor
2013-10-15 21:14 ` Ryan Johnson [this message]
2013-10-15 22:36 ` Christopher Faylor
2013-10-15 23:15 ` Larry Hall (Cygwin)
2013-10-15 23:16 ` Warren Young
2013-10-16 7:59 ` Corinna Vinschen
2013-10-16 21:27 ` Christopher Faylor
2013-10-17 3:46 ` Ryan Johnson
2013-10-17 8:48 ` Corinna Vinschen
2013-10-16 13:17 ` Bengt Larsson
2013-10-16 16:05 ` Corinna Vinschen
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