[Y2038] Fifth draft of the Y2038 design document

[Paul Eggert]

On 03/08/2017 02:28 AM, Albert ARIBAUD wrote:
> the only problem I see is if
> some weird code implicitly depends on tv_nsec's size being 'long'.


Although I have not found "weird code" like that in GNU applications I 
help maintain, I did find one instance of "weird code" back in 2012 when 
I was first looking into the problem: an example program in Kerrisk's 
book "The Linux Programming Interface" 
<http://man7.org/tlpi/code/online/dist/timers/t_clock_nanosleep.c.html>, 
which contains this:

             printf("... Remaining: %ld.%09ld",
                     (long) remain.tv_sec, remain.tv_nsec);

This fails on ABIs where tv_nsec is 'long long' and where 'long long' is passed differently from 'long'. (The code also fails on these ABIs if remain.tv_sec exceeds LONG_MAX, of course.)

So, although I'm mildly inclined to think it's OK to change tv_nsec to be wider than long, I suspect this change will break a few lower-quality applications in minor ways, and this is not a cost that we can entirely sweep under the rug.