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Date: Wed, 26 Aug 2015 12:48:00 -0000
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Subject: Re: 128-bit integer - nonsensical documentation?
From: Jeffrey Walton <noloader@gmail.com>
To: Jonathan Wakely <jwakely.gcc@gmail.com>
Cc: gcc-help <gcc-help@gcc.gnu.org>
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On Wed, Aug 26, 2015 at 8:22 AM, Jonathan Wakely <jwakely.gcc@gmail.com> wr=
ote:
> On 26 August 2015 at 12:04, Kostas Savvidis wrote:
>> The online documentation contains the attached passage as part of the "C=
-Extensions=E2=80=9D chapter. There are no actual machines which have an " =
integer mode wide enough to hold 128 bits=E2=80=9D as the document puts it.
>
> It's not talking about machine integers, it's talking about GCC
> integer modes. Several targets support that.
>
>> This would be a harmless confusion if it didn=E2=80=99t go on to say =E2=
=80=9C=E2=80=A6 long long integer less than 128 bits wide=E2=80=9D (???!!!)=
 Whereas in reality "long long int=E2=80=9D is 64 bits everywhere i have se=
en.
>
>
> Read it more carefully, it says you can't express an integer constant
> of type __int128 on such platforms.

Is there a way to detect the presence or availability of __int128 via
preprocessor macros?

Jeff