From: Richard Copley <rcopley@gmail.com>
To: Paul Eggert <eggert@cs.ucla.edu>
Cc: 29040@debbugs.gnu.org
Subject: bug#29040: Emacs 25 hangs on windows arbitrarily during search of a unicode file
Date: Thu, 2 Nov 2017 07:43:34 +0000 [thread overview]
Message-ID: <CAPM58og-a1k+xgNZiXEAA5ZUOJAnCS+KoM4mTxVunBhAHUB9TQ@mail.gmail.com> (raw)
In-Reply-To: <e30d771e-aeeb-72cc-ad0b-e46f8629f2bb@cs.ucla.edu>
On 2 November 2017 at 06:02, Paul Eggert <eggert@cs.ucla.edu> wrote:
>> +#define THREAD_ALIGNMENT COMMON_MULTIPLE (alignof (max_align_t),
>> GCALIGNMENT)
>> +
>> +static struct thread_state alignas (THREAD_ALIGNMENT) main_thread;
>
> Three questions:
>
> The Gnulib manual
> <https://www.gnu.org/software/gnulib/manual/html_node/stdalign_002eh.html>
> says, "Some compilers require the operand of _Alignas/alignas to be a single
> integer constant, not an expression: MSVC 7.0 through at least 10.0." (Also,
> <https://stackoverflow.com/questions/7895869/cross-platform-alignx-macro>
> suggests that this issue may also occur with VS2013, though VS2015 should be
> OK since it supports alignas.) Are any of these older compilers of concern
> when building Emacs?
I don't think so. How would one go about building Emacs with MSVC anyway?
>If so, the above change won't work for them.
> Why does the above code use 'alignof (max_align_t)' rather than 'alignof
> (struct thread_state)'? Doesn't the latter suffice?
For information, in the 64-bit GCC 7.2 toolchain from MinGW-W64, the two
are equal in value.
> C11 requires that a compiler must issue a diagnostic for a declaration like
> 'struct thread_state alignas (8) foo;' if the alignment of plain 'struct
> state' is greater than 8. Can I take it from this bug report that the
> Microsoft compilers do not conform to that part of the standard?
Microsoft compilers weren't mentioned at all. GCC didn't issue
a diagnostic.
> If so, we should add checks to verify this requirement where it is assumed elsewhere.
I think that is a good idea.
Thanks.
next prev parent reply other threads:[~2017-11-02 7:43 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-28 13:40 bug#29040: emacs-26 crash due to misaligned longjmp buffer in 64-bit MSYS2/MinGW-W64 build Richard Copley
2017-10-28 13:55 ` Eli Zaretskii
2017-10-28 14:10 ` bug#29040: Trouble with misaligned jmp_buf in 64-bit MinGW-64 runtime, in Emacs 26 Richard Copley
2017-11-02 6:02 ` bug#29040: Emacs 25 hangs on windows arbitrarily during search of a unicode file Paul Eggert
2017-11-02 7:43 ` Richard Copley [this message]
2017-11-02 11:10 ` Noam Postavsky
2017-11-02 15:50 ` Eli Zaretskii
2017-11-02 20:35 ` Paul Eggert
2017-11-02 20:46 ` Eli Zaretskii
2017-11-03 5:03 ` Paul Eggert
2017-11-03 8:37 ` Eli Zaretskii
2017-11-03 8:48 ` Paul Eggert
2017-11-03 8:50 ` Eli Zaretskii
2017-11-03 9:25 ` Paul Eggert
2017-11-03 10:02 ` Eli Zaretskii
-- strict thread matches above, loose matches on Subject: below --
2017-10-19 1:18 C K Kashyap
2017-10-19 3:34 ` Eli Zaretskii
2017-10-28 11:05 ` Richard Copley
2017-10-28 11:31 ` Eli Zaretskii
2017-10-28 12:10 ` Richard Copley
2017-10-28 12:19 ` Eli Zaretskii
2017-10-28 12:25 ` Richard Copley
2017-10-28 12:31 ` Richard Copley
2017-10-28 12:49 ` Eli Zaretskii
2017-10-28 13:56 ` bug#29040: " Richard Copley
2017-10-28 14:14 ` Eli Zaretskii
2017-10-28 15:58 ` Eli Zaretskii
2017-10-28 16:16 ` Richard Copley
2017-10-28 16:41 ` Eli Zaretskii
2017-10-29 18:10 ` Richard Copley
2017-11-01 19:16 ` Richard Copley
2017-11-02 7:39 ` Richard Copley
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