How to catch SIGINT for the current in Dart? - dart

Question

How can Ctrl+C or SIGINT be caught in a Dart program for the current process?
Something similar to this for Node:
process.on('SIGINT', function() {
// do stuff
});

Answer 1

It looks like the SIGUSR1 and SIGUSR2 fields used in the old answer are now deprecated. I got the following example working using the sigint field:
import "dart:io";
void main() {
var n = 0;
ProcessSignal.sigint.watch().listen((signal) {
print(" caught ${++n} of 3");
if (n == 3) {
exit(0);
}
});
}

Answer 2

I found the following test code at Unified Diff: tests/standalone/io/signals_test_script.dart
import "dart:io";
void main(args) {
int usr1Count = int.parse(args[0]);
int usr2Count = int.parse(args[1]);
var sub1;
var sub2;
void check() {
if (usr1Count < 0 || usr2Count < 0) exit(1);
if (usr1Count == 0 && usr2Count == 0) {
sub1.cancel();
sub2.cancel();
}
print("ready");
}
sub1 = ProcessSignal.SIGUSR1.watch().listen((signal) {
if (signal != ProcessSignal.SIGUSR1) exit(1);
usr1Count--;
check();
});
sub2 = ProcessSignal.SIGUSR2.watch().listen((signal) {
if (signal != ProcessSignal.SIGUSR2) exit(1);
usr2Count--;
check();
});
check();
}