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Subject: Re: [RFC] bpf.2: Use standard types and attributes
To:     Alexei Starovoitov <alexei.starovoitov@gmail.com>,
        bpf <bpf@vger.kernel.org>
Cc:     "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>,
        linux-man <linux-man@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>, libc-alpha@sourceware.org,
        gcc-patches@gcc.gnu.org
References: <20210423230609.13519-1-alx.manpages@gmail.com>
 <CAADnVQLf4qe3Hj7cjBUCY4wXb9t2ZjUt=Z=JuygRY0LNNHWAoA@mail.gmail.com>
From:   "Alejandro Colomar (man-pages)" <alx.manpages@gmail.com>
Message-ID: <56932c68-4992-c5e4-819f-a88f60b3f63a@gmail.com>
Date:   Sat, 24 Apr 2021 19:56:37 +0200
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Hello Alexei,

On 4/24/21 1:20 AM, Alexei Starovoitov wrote:
> Nack.
> The man page should describe the kernel api the way it is in .h file.

Why?

When glibc uses __size_t (or any other non-standard types) just because 
the standard doesn't allow it to define some types in some specific 
header, the manual pages document the equivalent standard type, (i.e., 
if glibc uses __size_t, we document size_t).

The compiler, AFAIK (gcc is CCd, so they can jump in if I'm wrong), 
using uint32_t in every situation where __u32 is expected.  They're both 
typedefs for the same basic type.

I can understand why Linux will keep using u32 types (and their __ user 
space variants), but that doesn't mean user space programs need to use 
the same type.

If we have a standard syntax for fixed-width integral types (and for 
anything, actually), the manual pages should probably follow it, 
whenever possible.  Any deviation from the standard (be it C or POSIX) 
should have a very good reason to be;  otherwise, it only creates confusion.

Thanks,

Alex

-- 
Alejandro Colomar
Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
Senior SW Engineer; http://www.alejandro-colomar.es/