On Wed, Nov 30, 2016 at 08:44:56AM +1100, Dave Chinner wrote:
> On Mon, Nov 28, 2016 at 02:42:35PM -0800, Eric Biggers wrote:
> > Since commit 7fda99a0c297 ("xfs.h: require transparent LFS for all
> > users"), building xfsprogs fails on a 32-bit platform because it does
> > not define _FILE_OFFSET_BITS=64 itself. Fix it by adding this to CFLAGS
> > in builddefs.in.
> >
> > Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
> > ---
> > include/builddefs.in | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/include/builddefs.in b/include/builddefs.in
> > index aeb2905..5219071 100644
> > --- a/include/builddefs.in
> > +++ b/include/builddefs.in
> > @@ -25,7 +25,7 @@ OPTIMIZER = @opt_build@
> > MALLOCLIB = @malloc_lib@
> > LOADERFLAGS = @LDFLAGS@
> > LTLDFLAGS = @LDFLAGS@
> > -CFLAGS = @CFLAGS@
> > +CFLAGS = @CFLAGS@ -D_FILE_OFFSET_BITS=64
>
> So, umm, why aren't these lines in configure.ac setting this already
> on your system?
>
> AC_SYS_LARGEFILE
> AC_NEED_LFS
>
> Cheers,
>
AC_SYS_LARGEFILE puts the _FILE_OFFSET_BITS definition in the generated config
header, not in CFLAGS. Normally projects use a config.h.in template that's
generated from configure.ac using autoheader. xfsprogs doesn't do this but
rather uses a non-generated file include/platform_defs.h.in. Since there is no
"#undef _FILE_OFFSET_BITS" in platform_defs.h.in, '#define _FILE_OFFSET_BITS 64'
doesn't gets included in platform_defs.h. Also, even if it was, then I think it
wouldn't always work because not all .c files in xfsprogs have platform_defs.h
as their first #include.
The reason AC_NEED_LFS still passes is that 'configure' includes a temporary
header confdefs.h rather than the final generated header, and the temporary
header includes the _FILE_OFFSET_BITS definition.
Eric
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