bug#20843: 24.5; Profiler error: "Invalid sampling interval"

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sat, 20 Jun 2015 17:47:21 -0400
> From: Ken Brown <kbrown@cornell.edu>
> CC: sva-news@mygooglest.com, 20843@debbugs.gnu.org
> 
> > Then I guess the configure-time test for setitimer should also test
> > for ITIMER_PROF.
> 
> I'd be glad to give this a try, but I don't have any experience writing 
> autoconf macros.  Is there a standard macro to test whether a function 
> accepts a particular argument?  If not, can you (or anyone) point me to 
> an example that I can imitate?

Actually, perhaps I misunderstood you: are you saying that Cygwin does
have ITIMER_PROF defined in the appropriate header, but when setitimer
is called with it, it always fails?  If so, we cannot test this at
configure time, because it means we will have to run a program, which
is not a good idea.

So in that case, I think we should simply disable the CPU profiler on
Cygwin using "#ifndef __CYGWIN__" or some such.

> >  Also, the diagnostics should be improved, as the
> > wording is misleading in that case.
> 
> As it stands, profiler-cpu-start reports "Invalid sampling interval" 
> whenever setup_cpu_timer fails to start the timer, regardless of the 
> reason.  I'll try to improve this.

Yes, please.

Thanks.