use warnings;
use strict;
use Time::HiRes qw/ clock_gettime clock_nanosleep
	CLOCK_REALTIME TIMER_ABSTIME /;
die "Don't have nanosleep" unless Time::HiRes::d_nanosleep();

use Time::HiRes qw/usleep/; # just for this fake "myfunc"
sub myfunc {
	printf "fired %.2f\n", clock_gettime(CLOCK_REALTIME);
	my $delay_us = int(rand 100000)+10000; # 110000us = 0.11s
	printf "delay %.2fs\n", $delay_us/1e6;
	usleep $delay_us;
}

my $next_s = int(clock_gettime(CLOCK_REALTIME))+1;
my $interval_s = 0.1;

my $run = 1; $SIG{INT} = sub { $run = 0 };
while ($run) {
	my $now_s = clock_gettime(CLOCK_REALTIME);
	$next_s += $interval_s while $next_s < $now_s;
	clock_nanosleep(CLOCK_REALTIME, $next_s*1e9, TIMER_ABSTIME);
	myfunc();
}