[Bug fortran/47571] [4.6/4.7 Regression] undefined reference to clock_gettime in Linux build of 02/01/2011

[ro at CeBiTec dot Uni-Bielefeld.DE]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47571

--- Comment #37 from ro at CeBiTec dot Uni-Bielefeld.DE <ro at CeBiTec dot Uni-Bielefeld.DE> 2011-03-15 16:24:01 UTC ---
>> I'd really like to see this fixed before 4.6.0: it is a regression from
>> 4.5 and makes fortran completely unusable on Tru64 UNIX for a relatively
>> minor gain on other platforms.
>
> Well, do we really have any actual gfortran users on Tru64? Whereas a
> high-resolution monotonic clock, while admittedly not a huge feature per se, is
> something that is now available to gfortran users on some rather more popular
> platforms.

Why would they tell me: `Hey, I'm using gfortran on Tru64 UNIX and all
is fine.'?   You will only learn if things break.

>>  If all else fails, I'd go as far as
>> advocating to revert the patch that introduced clock_gettime
>
> There has been a number of patches in this area more or less related to
> clock_gettime, so IMHO fixing it properly is simpler and less prone to
> introduce new regressions. My previous message in this PR hopefully does
> exactly this and introduces a patch which should fix it along the lines
> previously discussed. As my normal gcc development machine is packed in a box,
> I haven't been able to test it. Also, note that it won't apply cleanly as the
> paths are messed up (but the contents should otherwise apply fine). 

There have been some subsequent suggestions/updates, so I'm uncertain if
I should test this patch or wait for an update.

> As I mentioned previously, I'd prefer to commit it after the 4.6 release, but
> if the reviewer(s) feel it's safe I'm fine with getting it in for 4.6.

Now that 4.6 has branched, it's safer to commit to mainline after some
testing and only backport to 4.6 after it has proven correct.  If all
else fails, one could apply a hack to 4.6 along the lines of

#if defined(__alpha__) && defined(__osf__)
#undef HAVE_CLOCK_GETTIME
#endif

or some configure.ac equivalent.  Ugly but still better than completely
breaking Fortran.

    Rainer