From: Mark H Weaver <mhw@netris.org>
To: ludo@gnu.org (Ludovic Courtès)
Cc: Chaos Eternal <chaoseternal@shlug.org>, 18592@debbugs.gnu.org
Subject: bug#18592: FFI should have portable access to ‘errno’
Date: Sat, 24 Jan 2015 03:08:23 -0500 [thread overview]
Message-ID: <87twzgeh3c.fsf@yeeloong.lan> (raw)
In-Reply-To: <87h9vmy0zw.fsf@gnu.org> ("Ludovic \=\?utf-8\?Q\?Court\=C3\=A8s\=22'\?\= \=\?utf-8\?Q\?s\?\= message of "Mon, 19 Jan 2015 21:22:11 +0100")
ludo@gnu.org (Ludovic Courtès) writes:
> Chaos Eternal <chaoseternal@shlug.org> skribis:
>
>> Proposals to solve this bug:
>>
>> Proposal 1.
>>
>> Adding a keyword argument to pointer->procedure, if set to true, the
>> generated wrapper will check 'errno' immediately after ffi_call and
>> return the errno as second value.
>>
>> the proposed pointer->procedure maybe like this:
>> pointer->procedure return_type func_ptr arg_types #:return-errno
>>
>> Proposal 2.
>>
>> let pointer->procedure check return_type, if it is a list:
>> (func_return_type, 'errno)
>> then return multiple values, as errno be second value.
>
> That’s my favorite because it’s both pragmatic and extensible (we can
> also add support for h_errno, etc.)
We can't do this, because although it's not documented in our manual, a
list passed as a foreign type already has a meaning: it means a struct.
See 'parse_ffi_type' in foreign.c. I mentioned this fact on guile-user:
https://lists.gnu.org/archive/html/guile-user/2012-05/msg00037.html
Of the proposals given here, I would support #1, but maybe there's a
better option.
Thanks,
Mark
next prev parent reply other threads:[~2015-01-24 8:08 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-30 20:17 bug#18592: FFI should have portable access to ‘errno’ Frank Terbeck
2014-11-11 15:03 ` Mark H Weaver
2014-11-11 20:02 ` Frank Terbeck
2014-11-13 17:12 ` Mark H Weaver
2014-11-22 17:53 ` Chaos Eternal
2015-01-19 20:22 ` Ludovic Courtès
2015-01-24 8:08 ` Mark H Weaver [this message]
2015-01-24 8:22 ` Mark H Weaver
2015-01-24 10:33 ` Ludovic Courtès
2015-12-31 12:33 ` Nala Ginrut
2016-01-04 12:04 ` Nala Ginrut
2016-01-04 16:12 ` Mark H Weaver
2016-01-04 19:14 ` Nala Ginrut
2016-01-05 2:24 ` Chaos Eternal
2016-01-05 7:49 ` tomas
2016-01-05 8:38 ` Nala Ginrut
2016-01-05 15:08 ` Mark H Weaver
2016-01-05 19:21 ` Nala Ginrut
2016-02-18 8:25 ` Nala Ginrut
2016-02-18 13:30 ` Mark H Weaver
2016-02-19 5:02 ` Nala Ginrut
2016-02-26 11:18 ` Nala Ginrut
2016-03-03 17:36 ` Mark H Weaver
2016-03-03 20:32 ` tomas
2016-03-13 17:06 ` Nala Ginrut
2016-06-20 19:55 ` Mark H Weaver
2016-01-05 15:40 ` Mark H Weaver
2016-01-04 16:21 ` Mark H Weaver
2015-01-25 20:59 ` guile
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