Re: autoconf AC_SYS_LARGEFILE

[Ben Pfaff <blp@cs.stanford.edu>]

Brian May <bam@debian.org> writes:

> I am trying to get long file names to work in dar (uptodate
> debian/unstable).
> 
> So far, I don't think I have had any success (at least I
> don't see any evidence...).
> 
> I have traced it to the AC_SYS_LARGEFILE autoconf macro (autoconf 2.57),
> it outputs the following in config.log:

[...]

> 
> What is going on here? Any ideas?

It seems that you are being confused by the failure of this
single compilation, which is not a failure in the larger scheme
of things.  configure first tries large files without anything
special.  That fails, as should be expected on x86, which has
only 32-bit off_t by default, and the failure goes to the log.
configure then goes on to try large files with `#define
_FILE_OFFSET_BITS 64', which succeeds, again as expected.

> Is this a result of a buggy AC_SYS_LARGEFILE macro???

Everything works fine on my system here.  The relevant
./configure output is this:

    checking for special C compiler options needed for large files... no
    checking for _FILE_OFFSET_BITS value needed for large files... 64
    checking for _LARGE_FILES value needed for large files... no

This is correct: glibc doesn't need special C compiler options
for large files, _FILE_OFFSET_BITS should be set to 64, and no
_LARGE_FILES value is needed.

When I look at the generated config.h, I see this:

    /* Number of bits in a file offset, on hosts where this is settable. */
    #define _FILE_OFFSET_BITS 64

    /* Define for large files, on AIX-style hosts. */
    /* #undef _LARGE_FILES */

This is also correct.

If you see anything different in your configure script output or
in config.h (an error in either of them, for example), then let
me know.  Otherwise I think everything is fine here.
-- 
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 It is better to be seen at the opera with a man
 than at mass with a woman."
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