From:   Florian Weimer <fweimer@redhat.com>
To:     Cyril Hrubis <chrubis@suse.cz>
Cc:     Arnd Bergmann <arnd@arndb.de>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux API <linux-api@vger.kernel.org>,
        LTP List <ltp@lists.linux.it>,
        GNU C Library <libc-alpha@sourceware.org>,
        linux-arch <linux-arch@vger.kernel.org>
Subject: Re: [PATCH] uapi: Make __{u,s}64 match {u,}int64_t in userspace
References: <YZvIlz7J6vOEY+Xu@yuki>
        <CAK8P3a0x5Bw7=0ng-s+KsUywqJYa0tk9cSWmZhx+cZRBOR87ZA@mail.gmail.com>
        <YZyw56flmdQnBIuh@yuki>
Date:   Tue, 23 Nov 2021 20:50:31 +0100
In-Reply-To: <YZyw56flmdQnBIuh@yuki> (Cyril Hrubis's message of "Tue, 23 Nov
        2021 10:14:15 +0100")
Message-ID: <87a6hups6w.fsf@oldenburg.str.redhat.com>
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* Cyril Hrubis:

> As far as I can tell the userspace bits/types.h does exactly the same
> check in order to define uint64_t and int64_t, i.e.:
>
> #if __WORDSIZE == 64
> typedef signed long int __int64_t;
> typedef unsigned long int __uint64_t;
> #else
> __extension__ typedef signed long long int __int64_t;
> __extension__ typedef unsigned long long int __uint64_t;
> #endif
>
> The macro __WORDSIZE is defined per architecture, and it looks like the
> defintions in glibc sources in bits/wordsize.h match the uapi
> asm/bitsperlong.h. But I may have missed something, the code in glibc is
> not exactly easy to read.

__WORDSIZE isn't exactly a standard libc macro.

On musl, x86-64 x32 has __WORDSIZE == 64 depending on header-inclusion
order, but that's probably just a bug.

Thanks,
Florian