Re: [ANNOUNCE] linux-libc-headers 2.6.8.1

Erik Andersen
2004-08-30T07:48:49Z

On Mon Aug 30, 2004 at 12:24:22AM -0700, David S. Miller wrote:
> On Mon, 30 Aug 2004 00:28:56 -0600
> Erik Andersen <andersen@codepoet.org> wrote:
>
> > I really do not like this change. Since PAGE_SIZE has always
> > been a constant, the change you have made is likely to break a
> > fair amount of code, basically any code doing stuff like:
>
> It has never been a constant, and any portable piece of
> software needs to evaluate it not at compile time.
>
> When I first did the sparc64 port, the biggest source of
> portability problems was of the "uses PAGE_SIZE in some way"
> nature.
>
> This is a positive change, we should break the build of these
> apps and thus get them fixed.

There is no question that using PAGE_SIZE should be considered
harmful. But this particular change to the linux-libc-headers
makes it easy for the common case (bog standard x86) folk to keep
using a fixed PAGE_SIZE value, and keep writing crap code which
is now _guaranteed_ to blow chunks on mips, x86_64, etc.

I think outright removal of PAGE_SIZE from user space may be a
much better choice, with some sortof #error perhaps... Wouldn't
it be better for the whole world if people would get errors like

foo.c:10:2: #error "Don't use PAGE_SIZE, use sysconf(_SC_PAGESIZE)"

making people actually fix their code?

-Erik

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Erik B. Andersen http://codepoet-consulting.com/
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