Re: On time64 and Large File Support

[Paul Eggert]

On 2022-11-12 12:23, Wookey wrote:
> we can't just have everyone who enabled LFS sometime in the
> last 20 years suddenly being forced into the time_t change (can we?)

We've done it in the past.

AC_SYS_LARGEFILE originally was in Gnulib, before it migrated to 
Autoconf. Originally it affected only off_t; its effect on other types 
like ino_t came later. Hence people who initially used AC_SYS_LARGEFILE 
were later "suddenly forced" into an ino_t width change. Similarly for 
other non-off_t types that AC_SYS_LARGEFILE affects.

So there's longstanding precedent for AC_SYS_LARGEFILE changing the 
width of system types that were formerly unaffected. The difference is 
that time_t is more widely used than ino_t etc., and people are 
understandably more concerned about time_t changes.


Because of the concerns raised in this thread it's become clear that 
what's in Autoconf now is too drastic, and I've proposed (though not yet 
implemented) a change that will cause AC_SYS_LARGEFILE to continue to 
not affect time_t unless there's an affirmative request like 
"./configure --enable-year2038". I am waiting for feedback on that from 
Zack and others, and am hoping for quick turnaround on this because we 
do need a new Autoconf release.