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How can I measure time under a second?

by faq_monk (Initiate)
on Oct 08, 1999 at 00:29 UTC ( #722=perlfaq nodetype: print w/replies, xml ) Need Help??

Current Perl documentation can be found at perldoc.perl.org.

Here is our local, out-dated (pre-5.6) version:

In general, you may not be able to. The Time::HiRes module (available from CPAN) provides this functionality for some systems.

In general, you may not be able to. But if your system supports both the syscall() function in Perl as well as a system call like gettimeofday(2), then you may be able to do something like this:

    require 'sys/syscall.ph';

    $TIMEVAL_T = "LL";

    $done = $start = pack($TIMEVAL_T, ());

    syscall( &SYS_gettimeofday, $start, 0)) != -1
               or die "gettimeofday: $!";

       ##########################
       # DO YOUR OPERATION HERE #
       ##########################

    syscall( &SYS_gettimeofday, $done, 0) != -1
           or die "gettimeofday: $!";

    @start = unpack($TIMEVAL_T, $start);
    @done  = unpack($TIMEVAL_T, $done);

    # fix microseconds
    for ($done[1], $start[1]) { $_ /= 1_000_000 }

    $delta_time = sprintf "%.4f", ($done[0]  + $done[1]  )
                                            -
                                 ($start[0] + $start[1] );

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[Tux]: None work for me. My dead key is AltGr (right Alt)
[Tux]: And I just tested, neither do other Tk apps :) (95% of my Tk Apps is either just monitoring (no input) or input of just numbers). Something to investigate then
[choroba]: Maybe something like this?
[choroba]: I vaguely remember we had problems with dead keys in Tk at $work - 2, but I forgot all the details
[choroba]: but it was worse on MSWin than on Linux
[choroba]: (and OSX didn't exist yet)
[choroba]: Also, I'd try starting the App with the US layout and switch to the dead keys layout later

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