From: David Miller <davem@davemloft.net>
To: johannes@sipsolutions.net
Cc: adobriyan@gmail.com, linux-kernel@vger.kernel.org
Subject: Re: How do I printk <type> correctly?
Date: Thu, 23 Oct 2008 13:40:05 -0700 (PDT) [thread overview]
Message-ID: <20081023.134005.83296775.davem@davemloft.net> (raw)
In-Reply-To: <1224774806.6002.42.camel@johannes.berg>
From: Johannes Berg <johannes@sipsolutions.net>
Date: Thu, 23 Oct 2008 17:13:26 +0200
> > u64 SHOULD be printed with %llu/%llx, (unsigned long long):
> >
> > printk("%llu", (unsigned long long)u64_var);
> >
> > s64 SHOULD be printed with %lld/%llx, (long long):
> >
> > printk("%lld", (long long)s64_var);
>
> out of curiosity, why are there platforms that use an "unsigned long"
> for u64?
Because that type is large enough.
> An "unsigned long long" is 64-bits too even on 64-bit platforms, so
> why the difference? Are there any differences like alignment on some
> platforms?
I invite you to go make that change and then try to fixup all the
resulting build warnings. Some of us already made an attempt at
some point in the past. :-/
But it's just papering over the core problem, that we can't extend
gcc's automatic printf format type checking easily.
Even if we make u64 the same type everywhere, things like sector_t
and other types which do have to vary by architecture will need
to be casted.
next prev parent reply other threads:[~2008-10-23 20:40 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-23 11:41 How do I printk <type> correctly? Alexey Dobriyan
2008-10-23 11:51 ` David John
2008-10-23 12:06 ` Alexey Dobriyan
2008-10-23 15:13 ` Johannes Berg
2008-10-23 20:40 ` David Miller [this message]
2008-10-24 8:41 ` Johannes Berg
2008-10-28 23:11 ` Randy Dunlap
2008-10-29 6:15 ` Artem Bityutskiy
2008-10-29 8:00 ` Artem Bityutskiy
2008-10-29 15:34 ` Randy Dunlap
2008-10-29 15:36 ` Artem Bityutskiy
2008-10-29 15:43 ` Randy Dunlap
2008-11-05 18:23 ` Randy Dunlap
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