Re: [PATCH] AC_SYS_LARGEFILE: define _DARWIN_USE_64_BIT_INODE conditionally

[Eric Blake]

On 01/15/2013 05:01 PM, PHO wrote:
> * lib/autoconf/specific.m4 (AC_SYS_LARGEFILE): This macro was
> accidentally defining _DARWIN_USE_64_BIT_INODE with AH_VERBATIM so the
> variable was defined even when $enable_largefile = no. The bug also
> caused inconsistency between AH_HEADER and confdefs.h thus
> AC_COMPUTE_INT(VAR, [sizeof(ino_t)]) produced a wrong result,
> i.e. 32-bit ino_t for configuration time and 64-bit ino_t for
> build/run time.
> ---

Thanks for the report. but I don't think this patch is quite right.  Can
you please provide more details, such as a minimal configure.ac to
provoke the issue, and the resulting config.h that gets generated
incorrectly?

>  lib/autoconf/specific.m4 | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/autoconf/specific.m4 b/lib/autoconf/specific.m4
> index bbfa24a..4b20a63 100644
> --- a/lib/autoconf/specific.m4
> +++ b/lib/autoconf/specific.m4
> @@ -171,8 +171,9 @@ if test "$enable_largefile" != no; then
>    AH_VERBATIM([_DARWIN_USE_64_BIT_INODE],
>  [/* Enable large inode numbers on Mac OS X 10.5.  */
>  #ifndef _DARWIN_USE_64_BIT_INODE
> -# define _DARWIN_USE_64_BIT_INODE 1
> +# undef _DARWIN_USE_64_BIT_INODE
>  #endif])

Unconditionally undefining a macro when it is already inside an #ifndef
block is pointless. Are you stating that you don't need the AH_VERBATIM
at all, and can instead just use an AC_DEFINE to get the semantics you
want?  And these days, compiling without large file support is rather
anti-climactic; gnulib, for example, has already decided that it is much
easier to always insist on large file support than it is to try to make
it user-configurable.

> +  AC_DEFINE([_DARWIN_USE_64_BIT_INODE], [1])
>  fi
>  ])# AC_SYS_LARGEFILE
> 
> --
> 1.8.0.1
> 

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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