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Re: SIGPOLL on Darwin
From: |
Reuben Thomas |
Subject: |
Re: SIGPOLL on Darwin |
Date: |
Tue, 31 Jan 2012 18:07:43 +0000 |
On 31 January 2012 15:51, Paul Eggert <address@hidden> wrote:
> On 01/31/2012 07:19 AM, Reuben Thomas wrote:
>> SIGPOLL seems to be unimplemented on Darwin
>
> I don't offhand see an easy way to implement it in Gnulib,
> so perhaps it's better that Gnulib doesn't define it.
> (Sorry, I don't know the context.)
I am interested in two things:
1. The symbol SIGPOLL.
2. The functionality around it.
The relevant bit of header says:
#if (defined(_POSIX_C_SOURCE) && !defined(_DARWIN_C_SOURCE))#define
SIGPOLL 7 /* pollable event ([XSR] generated, not supported)
*/#else /* (!_POSIX_C_SOURCE || _DARWIN_C_SOURCE) */#define SIGIOT
SIGABRT /* compatibility */#define SIGEMT 7 /* EMT instruction
*/#endif /* (!_POSIX_C_SOURCE || _DARWIN_C_SOURCE) */
(I haven't got the headers myself, this was in a bug report.)
I assume that not defining _DARWIN_C_SOURCE is not an option, hence
the only workaround would be to have gnulib define
#define SIGPOLL 7
or, as suggested in this thread
#define SIGPOLL SIGIO
But this would presumably create problems for code that assumed
SIGPOLL's existence meant that the relevant functionality (whatever
that is) is supported. I have no idea what "generated, not supported"
means above.
If anyone who actually knows about how Mac OS works would like to
comment, I'd be grateful; it'd be wonderful to see a solution in
gnulib.
> diff --git a/m4/extensions.m4 b/m4/extensions.m4
> index 0bfaef6..58280cf 100644
> --- a/m4/extensions.m4
> +++ b/m4/extensions.m4
> @@ -75,6 +75,10 @@ AC_BEFORE([$0], [AC_RUN_IFELSE])dnl
> #ifndef _GNU_SOURCE
> # undef _GNU_SOURCE
> #endif
> +/* Enable POSIX symbols on MacOS X. */
> +#ifndef _POSIX_C_SOURCE
> +# undef _POSIX_C_SOURCE
> +#endif
> /* Enable threading extensions on Solaris. */
> #ifndef _POSIX_PTHREAD_SEMANTICS
> # undef _POSIX_PTHREAD_SEMANTICS
I don't know whether this has a downside; I don't use Mac OS.
--
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