Re: [PATCH] Check for POSIX_MADV_WILLNEED to support building against the LSB

[Mark Kettenis <mark.kettenis@xs4all.nl>]

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> From: Michael Hope <michael.hope@linaro.org>
> Date: Mon, 11 Jun 2012 18:16:51 +1200
> 
> On 11 June 2012 17:59, Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
> >> Date: Mon, 11 Jun 2012 16:25:22 +1200
> >> From: Michael Hope <michael.hope@linaro.org>
> >>
> >> The Linux Standard Base APIs include posix_madvise() but don't define
> >> values for the 'advice' argument.  Check to see if POSIX_MADV_WILLNEED
> >> is defined before using.
> >
> > What real-world problem does this fix?
> 
> Being able to build GDB using the LSB tools so that you can make a
> binary release that works on any Linux distro from RHEL4 and above.
> We use it for the linaro-toolchain-binaries.

I fear you're using a broken toolchain, because...

> > It makes no sense to have
> > posix_madvise() but not define any values for the 'advice' argument.
> > I'd say this is a "bug" in LSB.  Either they should drop
> > posix_madvise() from the standard, or include at least the 'advice'
> > values required by POSIX.
> 
> The LSB has a policy of not dropping functions.  I can suggest that
> they add the advise values for a later version but that will take some
> time and won't cover existing LSB releases.

Both posix_madvise():

http://www.linuxbase.org/navigator/browse/int_single.php?cmd=list-by-name&Iname=posix_madvise&Ilibrary=libc

and POSIX_MADV_WILLNEED:

http://www.linuxbase.org/navigator/browse/headgroup.php?cmd=list-byheadgroup&HGid=56

were added in LSB 3.2.