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Re: Async-signal-safe access to __thread variables from dlopen()ed libraries?
- From: Ian Lance Taylor <iant at google dot com>
- To: Torvald Riegel <triegel at redhat dot com>
- Cc: Rich Felker <dalias at aerifal dot cx>, "Carlos O'Donell" <carlos at redhat dot com>, Paul Pluzhnikov <ppluzhnikov at google dot com>, Roland McGrath <roland at hack dot frob dot com>, Richard Henderson <rth at twiddle dot net>, GNU C Library <libc-alpha at sourceware dot org>, Andrew Hunter <ahh at google dot com>, Alexandre Oliva <aoliva at redhat dot com>
- Date: Wed, 2 Oct 2013 06:02:40 -0700
- Subject: Re: Async-signal-safe access to __thread variables from dlopen()ed libraries?
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On Wed, Oct 2, 2013 at 2:16 AM, Torvald Riegel <firstname.lastname@example.org> wrote:
> On Fri, 2013-09-20 at 13:52 -0400, Rich Felker wrote:
>> On Fri, Sep 20, 2013 at 01:41:37PM -0400, Carlos O'Donell wrote:
>> > * Discuss the ISO C11 implications.
>> > ISO C11 wording in 188.8.131.52 p5:
>> The ISO C text on signal handlers is rather irrelevant.
> While you can certainly target POSIX and treat what C defines as
> secondary regarding signal handling, I don't agree that C's definitions
> are irrelevant: If you want portable C11 code, you will rely on what ISO
> C specifies.
Yes. However, the C11 wording is irrelevant with regard to what glibc
should provide. glibc is not a portable C11 library. It's a GNU
library. At a bare minimum glibc needs to provide POSIX.1 support.
And it's fine for a GNU library to provide more--e.g., glibc provides
__thread variables long before they were in any standard.