Re: autoconf problem with large files on HP-UX?

[Jim Meyering]

Thanks for the report, Bob.
[Bob reported (included below) that the largefile test from autoconf-2.49c
 doesn't work on HP-UX 10.20. ]

This test (note the ULL suffixes) is compiled without error by /bin/cc
on an HPUX10.20:

  #define _FILE_OFFSET_BITS 64
  #include <sys/types.h>
  int a[(off_t) 9223372036854775807ULL == 9223372036854775807ULL ? 1 : -1];
  int main () { return 0; }

The current test in configure lacks the ULL suffixes, so it fails:

  cc: "k.c", line 3: warning 602: Integer constant exceeds its storage.
  cc: "k.c", line 3: warning 602: Integer constant exceeds its storage.

One work-around is to change acspecific.m4's _AC_SYS_LARGEFILE_TEST_INCLUDES
test to first see if the ULL suffix is accepted by the compiler,
and then set e.g., ac_ull=ULL and use $ull in the test program.

Jim

Bob Proulx <address@hidden> wrote:
| I have been trying to track down a couple of problems with the new
| autoconf in general.  One of them is the large file checking.  It is
| broken.  I can't quite figure it out.  This is on HP-UX.
|
| fileutils-4.0.37:
| ./configure
| [...]
| checking for special C compiler options needed for large files... no
| checking for _FILE_OFFSET_BITS value needed for large files... no
| checking for _LARGE_FILES value needed for large files... no
|
| config.h:
| /* Number of bits in a file offset, on hosts where this is settable. */
| /* #undef _FILE_OFFSET_BITS */
|
| Huh?  Something is not right here.  That should be defined to be 64.
| It looks to me like autoconf is not getting this right and large files
| are not getting set up.  I went back to an older 4.0.27 and this is
| what it used to say there.
|
| fileutils-4.0.27:
| checking for special C compiler options needed for large files... no
| checking for _FILE_OFFSET_BITS value needed for large files... no
| checking for _LARGEFILE_SOURCE value needed for large files... 1
| checking for _LARGE_FILES value needed for large files... no
| checking for _XOPEN_SOURCE value needed for large files... no
|
| config.h:
| /* Number of bits in a file offset, on hosts where this is settable. */
| /* #undef _FILE_OFFSET_BITS */
|
| /* Define to make ftello visible on some hosts (e.g. HP-UX 10.20). */
| #define _LARGEFILE_SOURCE 1
|
| That does not look completely right either.  It certainly is
| different.  But perhaps it worked out somehow.  I crawled through the
| system headers and on first pass it looks like _LARGEFILE_SOURCE is
| only effective if _FILE_OFFSET_BITS is set too.  I think both
| _FILE_OFFSET_BITS=64 and _LARGEFILE_SOURCE are needed.  Here is what
| the docs (/usr/share/doc/lg_file.txt) say about these macros:
|
| : _LARGEFILE_SOURCE
| :
| : This compile option provides two new interfaces, ftello() and
| : fseeko(), to the developer. ftello() and fseeko() will behave just as
| : ftell() and fseek() except, ftello() will return an off_t instead of a
| : long int and fseeko() will take an off_t as it's second parameter
| : instead of a long int.
|
| This only makes the 'o' versions available.  I checked the headers and
| that is only if _FILE_OFFSET_BITS was previously defined to be 64.  So
| this should not be enough just by itself.  you need
| _FILE_OFFSET_BITS=64 and you need _LARGEFILE_SOURCE.
|
| : _FILE_OFFSET_BITS
| :
| : This compile option will specify what type of compile environment the
| : developer will use. If the compile option is set to 64, then various
| : data types, structures, and interfaces will be changed to their 64-bit
| : equivalents. If the compile option is set to 32, then these items will
| : be set to 32-bits (32 bits is the default).This compile option is used
| : as _FILE_OFFSET_BITS=32 or _FILE_OFFSET_BITS=64.
|
| I have always used the define _FILE_OFFSET_BITS=64 to enable large
| files.  This is the one we want.  I think the test needs to test for
| _FILE_OFFSET_BITS=64 first and then if _LARGEFILE_SOURCE second
| because it has no effect if _FILE_OFFSET_BITS is not 64.
|
| If I force _FILE_OFFSET_BITS=64 as part of CFLAGS when I configure
| then everything works and I can access large files again.
|
| Here is a snippet from the config.log file.  I don't see the define
| happening and so of course it fails.
|
| configure:2233: checking for _FILE_OFFSET_BITS value needed for large files
| configure:2254: cc -c -g  conftest.c >&5
| cc: "configure", line 2244: warning 602: Integer constant exceeds its storage.
| cc: "configure", line 2244: warning 602: Integer constant exceeds its storage.
| configure:2288: result: no
|
| I was sure this used to work with the included largefile.m4 but the
| built in one in autoconf-2.49c appears broken.  I don't have the brain
| cells left tonight to dig into that part of it to figure that out.
| Tag, you are it.
|
| Bob
|
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